Country · Asia
Thailand
Every profile recorded in Thailand, native or introduced.
- Species
- 243
- Families
- 28
- Genera
- 92
- Found only here
- 33
- Photographed
- 243 of 243
Where it isAsia
Shares its fishes withspecies recorded in both
Found only here33
33 of these profiles carry Thailand and no other country. That is not the same as endemic. Most of these distributions are only half recorded.

Abbottina rivularisChinese False Gudgeon
Cyprinidae · Basilewsky, 1855
Native to continental China, the Korean peninsula, and southern Japan. Type locality is given only as 'Lakes and rivers, northern China', with the type series possibly originating from the Pai-ho River near Beijing. It has been widely introduced and is considered invasive elsewhere, including the Mekong river basin (records from Laos and Thailand), Salween river (Myanmar), northern Japan, Taiwan, Turkmeni...

Acanthopsoides molobrion
Cobitidae · Siebert, 1991
Acanthopsoides spp. are most closely related to the horse-faced loaches of the genus Acantopsis with which they often co-occur in nature, and thus commonly referred to as 'dwarf horse-face loaches'. The genus currently comprises five species of which four were described by Siebert (1991); these were discovered in existing museum holdings...

Acantopsis dialuzonaHorseface Loach
Cobitidae · van Hasselt, 1823
Juveniles of this 'species' (probably a group of species - see 'distribution') are traded in large numbers but it's still uncommon to see adult specimens in the hobby suggesting their needs are not catered for often enough. This is a shame as when maintained properly they're hardy, long-lived and interesting aquarium residents. Other trade names include 'long-nosed' and 'banana' loach. Please note although certain that more than one species is being tr...

Acrochordonichthys gyrinusFalcate Chameleon Catfish
Akysidae · Vidthayanon & Ng, 2003
As in other members of the genus body colouration in this species is variable, even among individuals collected from a single locality, although a few regularities have been observed which can be used to distinguish certain species from one another. This is thought related to the fact that Acrochordonichthys spp. periodically shed their skins and appear paler post-moulting.

Acrochordonichthys rugosusAsian Banjo Catfish
Akysidae · Bleeker, 1846
This is the most commonly-encountered representative of the genus in the aquatic trade though is by no means common. As in other members of the genus body colouration is highly variable, even among individuals collected from a single locality, although a few useful regularities have been observed which can be used to distinguish certain species. This is thought related to the fact that Acrochordonichthys spp. periodically shed their skins and appear paler post-moulting. A. rugosus lends its ...

Acrochordonichthys septentrionalisMae Klong Chameleon Catfish
Akysidae · Ng & Ng, 2001
As in other members of the genus body colouration in this species is variable, even among individuals collected from a single locality, although a few regularities have been observed which can be used to distinguish certain species from one another. This is thought related to the fact that Acrochordonichthys spp. periodically shed their skins and appear paler post-moulting.

Akysis hendricksoniHendrickson's Stream Catfish
Akysidae · Alfred, 1966
This species is among the few members of the family to have been exported for the aquarium hobby. It can be differentiated from all other Akysis species by the following combination of characters: head length 17.7-26.5% of standard length (SL); head width 25.4-28.7% SL; body depth at anus 13.0-17.0% SL; caudal peduncle depth 8.1-10.1% SL; interorbital di...

Akysis maculipinnisSpotfin Stream Catfish
Akysidae · Fowler, 1934
This species has been exported for the aquarium hobby and ranks among the smaller members of the family. It can be differentiated from all other Akysis species by the following combination of characters: head length 22.0-28.6% of standard length (SL); caudal peduncle depth 8.8-10.7% of SL; anal-fin base length 15.2-19.1% of SL; eye diameter 12-16% of head length (HL); nasal barbel length 57 92% of HL; posession of 3-4 serrae on the posterior edge ofspine; body patterning mottled with indistinct ...

Akysis pulvinatusKra Stream Catfish
Akysidae · Ng, 2007
This species has been exported for the aquarium hobby on an extremely limited basis. It can be differentiated from all other Akysis species by the following combination of characters: head length 27.6–29.8% of standard length (SL); head width 21.9–25.1% SL; caudal peduncle depth 9.4–10.3% SL; length ofbase 23.0–25.2% SL; nasal barbel len...

Akysis variusVariable Stream Catfish
Akysidae · Ng & Kottelat, 1998
This species is among the smaller members of the family. It can be differentiated from all other Akysis species by the following combination of characters: caudal peduncle length 16.1-19.8% of standard length (SL); caudal peduncle depth 6.5-9.3% SL; length of adipose-fin base 25.6-29.5% SL; interorbital distance 42.0-46.0% of head length (HL), eye diameter 13.0-20.0% HL; length of nasal barbel 44.0-66.0% HL; lateral margins of the head appear straight when viewed from above; possession of 0-5 se...

Akysis vespaOrange-Banded Stream Catfish
Akysidae · Ng & Kottelat, 2004
This species is among the few members of the family to be exported for the aquarium hobby and we've also seen it on sale under various names such as 'orange-banded stone catfish', 'orange micro bumblebee catfish', 'Burmese orange mini bee catfish' or more simply 'wasp catfish'. Though the majority of forms are yellowish to orange in colouration there appears to exist a bright red variant which to date we've only seen in photos.

Ambastaia nigrolineataBlack-Lined Loach
Botiidae · Kottelat & Chu, 1987
This specie is relatively rare in the aquarium trade and much sought after by enthusiasts as a result. It looks relatively similar to A. sidthimunki but according to the original description by Kottelat and Chu (1987) can be told apart by colour patterning which uniquely consists of a solid da...

Ambastaia sidthimunkiDwarf Chain Loach
Botiidae · Klausewitz, 1959
This species was lost to the hobby for several years prior to the turn of the century and when commercially-produced stock first came onto the market prices were very high. It's now readily available, though, and while never particularly cheap is considerably less expensive.

Amblypharyngodon chulabhornaePrincess Carplet
Cyprinidae · Vidthayanon & Kottelat, 1990
The genus Amblypharyngodon currently contains five valid species, and A. chulabhornae can be distinguished from congeners by the following combination of characters: 42-50 (vs. 50-79) scales in the lateral row; lateral line incomplete with 6-7 (vs. 7-23) perforated scales; 4-5 scales on a transverse row between the lateral line and pelvic-fin base. All members of the genus lack barbels.

Badis khwae
Badidae · Kullander & Britz, 2002
Like most badids this species is poorly documented and has yet to find significant popularity in the aquarium hobby, though given its restricted natural distribution it is unlikely ever to be available in large numbers. Within the genus it is most easily confused with B. ruber and B. siamensis but both these species have rows of dark spot-like markings on the flanks which are lacking in B. khwae. The three also differ in the shape of the dark marking on the caudal peduncle; in B. ruber it is rel...

Badis siamensis
Badidae · Klausewitz, 1957
Like most badids this species is poorly documented and has yet to find significant popularity in the aquarium hobby; to date it has only been exported in very limited numbers. It was for a number of years known as Badis badis siamensis and will be seen labelled as such in older literature. Within the genus it is most easily confused with B. khwae and B. ruber but can be identified by the flank patterning which consists of rows of horizontally-arranged dark markings. In B. ruber these appear mor...

Bagrichthys majusculusWhite-Whisker Lancer
Bagridae · Ng, 2002
The vernacular name 'lancer' is derived from the extended dorsal spine possessed by several members of the genus, which currently contains 7 species. Among them B. majusculus is most similar to B. macracanthus and B. vaillantii but can be told apart from both by possession of longer pectoral-fin spines (length 15.8 - 20.7 % SL vs. 11.5 - 16.2 %), from the former by possession of a larger adipose fi...

Bagrichthys obscurus
Bagridae · Ng, 1999
The vernacular name 'lancer' is derived from the extended dorsal spine possessed by several members of the genus, which currently contains 7 species. B. obscurus is diagnosable from congerners by the following combination of characters: mouth opening relatively small and narrow; oral dentition significantly reduced; dorsal-fin spi...

Balitoropsis zollingeri
Balitoridae · Bleeker, 1853
An obligate dweller of swiftly-flowing streams and headwaters containing clear, oxygen-saturated water. It often inhabits riffles and runs and is likely to show a preference for shallower zones. Substrates are generally composed of gravel, rocks, boulders or bedrock carpeted with a rich biofilm formed by algae and other micro-organisms. Juveniles are often found in slower-moving stretches with gravel substrate and submerged tree roots. In both cases patches of aquatic plants are only occasionally pres...

Barbodes aurotaeniatus
Cyprinidae · Tirant, 1885
B. aurotaeniatus is uncommon in the aquarium trade. Following Kottelat (1998) it has a single pair of maxillary barbels, a complete lateral line and colour pattern usually comprising four small, vertically-orientated black markings on the flanks (located above anterior lateral line origin, below dorsal-fin origin, below posterior end of dorsal-fin base and on caudal peduncle, respectively) and one on the dorsal surface, below dorsal-fin origin.

Barbodes binotatusSpotted Barb
Cyprinidae · Valenciennes, 1842
This species is so ubiquitous across its natural range that it's often referred to simply as 'common barb'. Basic adult colour pattern consists of a small, dark spot at the base of the dorsal-fin origin and another on the caudal peduncle but overall appearance varies somewhat depending on origin, with the anterior dark spot enlarged ventrally forming a bar or posterior spot extending into the caudal-fin, for example. The spots may also appear darker or lighter in some individuals.

Barbodes lateristrigaSpanner Barb
Cyprinidae · Valenciennes, 1842
This species is commonly-referred to as 'T-barb' in some countries. It's closely-affiliated with and sometimes traded as the congener B. kuchingensis but that species can be told apart by colour pattern comprising a prominent row of dark spots along the lateral line, plus a short, horizontally-orientated streak extending from the upper part of the operculum. In B. lateristriga the lateral markings usually form a solid stripe and there is no streak extending from the operculum.

Barbonymus altusRed-tailed Tinfoil Barb
Cyprinidae · Günther, 1868
This is one of two species sold with the common/trade name of "tinfoil barb", the other being the more widely-recognised B. schwanenfeldii. Despite this it appears that B. altus is just as widely available as B. schwanenfeldii and in many cases is seen on sale more regularly. Unfortunately both are usually offered at a small size (usually around 2 - 3"/5 - 7.5cm) with little to no information regarding the eventual size of the fish. Although B. altus is the ...

Barbonymus gonionotus
Cyprinidae · Bleeker, 1849
The genus Barbonymus was erected by Kottelat in 1999 and contains former members of Barbodes from southeast Asia. The type species is B. schwanenfeldii and currently there exist only three other representatives; B. altus, B. collingwoodii and B. gonionotus. The latter two are rare in the hobby although an SF member has kept B. gonionotus in the past so they are worth looking out for if you harbour an...

Barbonymus schwanefeldiiTinfoil barb
Cyprinidae · Bleeker, 1854
This is one of two species traded under the vernacular name 'tinfoil barb', the other being the less well-known congener B. altus. Despite this it appears that B. altus is just as widely available as B. schwanefeldii and in many cases is seen on sale more regularly. Unfortunately both are usually offered at a small size (usually around 50 - 75 mm) with little to no information regarding the eventual size of the fish.

Batasio feruminatus
Bagridae · Ng & Kottelat, 2008
Batasio spp. are obligate inhabitants of headwater streams and the upper reaches of smaller rivers characterised by shallow, fast-flowing, highly-oxygenated stretches of riffles and runs broken up by pools or cascades in some cases. Images of the Ataran correspondingly depict flowing sections of forest-shaded, seemingly well-oxygenated headwaters containing clear water, a mixed sand/rock substrate and lots of submerged driftwood/leaf litter.

Batasio fluviatilis
Bagridae · Day, 1888
Batasio havmolleri (Smith, 1931) is currently considered a junior synonym of B. fluviatilis. Members of the genus Batasio are characterised by the following combination of characters; laterally-compressed body shape; presence of large sensory pores on the head; a narrow mental region; a pair of prominent posterior proces...

Batasio tigrinus
Bagridae · Ng & Kottelat, 2001
Members of the genus Batasio are characterised by the following combination of characters; laterally-compressed body shape; presence of large sensory pores on the head; a narrow mental region; a pair of prominent posterior processes on the anterior portion of the vomer; a transversely elongated, bar-like entopterygoid; close contact between the metapterygoid and quadrate.

Belontia hasseltiJava Combtail
Osphronemidae · Cuvier, 1831
This species is also referred to by the vernacular name 'Malay combtail'. In terms of external characters it differs most obviously from its only congener, B. signata by its overal brownish grey (vs. reddish) body colouration and presence of a mosaic-type patterning in the unpaired fins (vs. absence). The position of relatedness of the genus Belontia with respect to other anabantoids remains somewhat...

Betta imbellisCrescent Betta
Osphronemidae · Ladiges, 1975
B. imbellis is included in the Betta splendens complex of closely-related species within the genus, of which members share the following set of characters: head length short 22-31 % SL; often a brightly-coloured body; iris of the eye with iridescent green or blue patches; body elongate or slender; opercles parallel when head viewed dorsally; caudal-fin rays red or brown and contrasting with the iridescent interradial membranes; unpaired fins without an irides...

Betta kuehnei
Osphronemidae · Schindler & Schmidt, 2008
It can be told apart from other members of the B. pugnax group by the following characters: caudal fin rounded in both males and females; chin bar and second postorbital stripe absent; adult males possess intensive blue or bluish-green iridescent (blackish in preservation) colouration on the sides of the head and throat extending from the snout tip to posterior edge of opercle; possession of two central body stripes, the upper extending from the pec...

Betta mahachaiensis
Osphronemidae · Kowasupat, Panijpan, Ruenwongsa & Sriwattanarothai, 2012
Known only from a handful of localities in Bangkok, Samut Sakhon, Samut Songkhram and Samut Prakan provinces in central Thailand, all of which lie on the coast of the Gulf of Thailand. Most habitats are in close proximity to Bangkok, which continues to expand rapidly, are considered under extreme threat, and recent surveys have failed to confirm that the fish is still present in Samut Songkhram and Samut Prakan.

Betta pallida
Osphronemidae · Schindler & Schmidt, 2004
Has been collected from a slowly-moving creek which ranged in depth from 20-50 cm. The water was clear and slightly-stained with tannins and the subtrate was covered by a layer of leaf litter. PH was 6.3, conductivity 82 µS/cm and water temperature 25.5°C. At another locality pH was 6.5, conductivity 69 µS/cm and water temperature 26.6 °C.

Betta pi
Osphronemidae · Tan, 1998
B. pi is included in the Betta waseri group of closely-related species within the genus, an assemblage within which members share the following combination of characters: base body colouration clay yellow; opercle scales iridescent gold in mature males of all species except B. tomi; throat with black markings which join with black lower jaw in some species; no chin bar.

Betta prima
Osphronemidae · Kottelat, 1994
It can be told apart from other members of the B. pugnax group by the following characters: second postorbital stripe on opercle complete; no transverse bars in caudal-fin; 20-22 predorsal scales; preanal length 50.6-54.8 % SL. Not all authors consider it a member of this group, however, with some placing it in the B. picta complex, e.g., Schindler and Schmidt (2006). The genus is th...

Betta siamorientalis
Osphronemidae · Kowasupat, Panijpan, Ruenwongsa & Jeenthong, 2012
This species was considered a colour form of the closely-related B. imbellis and commonly-referred to as 'black imbellis' prior to description due to its blackish opercle and body. It's also previously been confused with B. splendens due to the colour of the vertical opercular bars which tend to be reddish (but may also be pale red, greenish-silvery, plain silvery or without colour in some populations), but DNA analysis has demonstrated it...

Betta simplex
Osphronemidae · Kottelat, 1994
B. simplex is included in the Betta picta group/complex of closely-related species within the genus, an assemblage comprising species with the following shared characters: unpaired fins rounded (anal-fin sometimes tapering to a blunt point); anal-fin rays I-III, 18-24; dark marginal band on anal and caudal fins, more pronounced in mature males; presence of pre-orbital and post-orbital stripes; presence of chin bar on throat; iridescent green, gold, or blue scales on opercle.

Betta smaragdinaEmerald Betta
Osphronemidae · Ladiges, 1972
This species is included in the Betta splendens complex of closely-related species within the genus, of which members share the following set of characters: head length short 22-31 % SL; often a brightly-coloured body; iris of the eye with iridescent green or blue patches; body elongate or slender; opercles parallel when head viewed dorsally; caudal-fin rays red or brown and contrasting with the iridescent interradial membranes; unpaired fins without an iridescent margin; opercle with red or blue vertical bars in males; dorsal-fin rays 0-II, 7-9; anal-fin rays II-V, 21-26.

Betta splendensSiamese Fighting Fish
Osphronemidae · Regan, 1910
This species' common name is derived from the tradition of keeping the fish in order to fight against each other in organised 'bouts' upon which participants and onlookers place wagers. It has been extensively line-bred for vigour, strength, and the ornamental trade, and hybridised with the congeners B. imbellis, B. smaragdina, and B. mahachaiensis.

Boraras maculatusDwarf Rasbora
Cyprinidae · Duncker, 1904
Within the genus Boraras this species is most similar to B. naevus, though in the latter the red body colouration does not extend into the head. The two also differ in the following characters: anteriormost lateral blotch of comparable size in both sexes in B. maculatus vs. significantly larger in male than female B. naevus; 9-10 + 9 principal caudal-fin rays vs. 9 + 8; 26-29 lateral scales vs. 24-26; i.6.i. pelvic-fin rays vs. i.5.i.

Boraras micros
Cyprinidae · Kottelat & Vidthayanon, 1993
Bung Khong Long is a lake and confirmed locality in Nong Khai province, Thailand. Aquatic plant species in the lake and surrounding floodplain include Hydrilla verticillata, Ceratophyllum dermersum, Chara zeylanica and Blyxa echinosperma. Salvinia cucullata is found floating on the surface and emergent plants comprise Eleocharis dulcis, Nelumbo nucifera, Lepironia articulata and Nymphaea lotus.

Boraras naevus
Cyprinidae · Conway & Kottelat, 2011
Known only from southern (peninsular) Thailand with the type series originating from a swamp some 83 km north of Surat Thani city, Surat Thani province. It's been recorded at additional locations, all within the lower Tapi river drainage on the Gulf of Thailand slope of the Malay Peninsula. In the description Conway and Kottelat (2011) report the occurence of a similar-looking, possibly conspecific fish on the Andaman Sea side of the Peninsula, close to Trang province.

Boraras urophthalmoides
Cyprinidae · Kottelat, 1991
The anatomical structure of miniaturised cyprinids can vary greatly, and there are two principle 'groupings' with some species possessing intermediate features to some degree. The first contains those fishes which though small are essentially proportionally dwarfed versions of their larger relatives, e.g., Barboides, Microdevario, Microrasbora, Horadandia, Boraras, Sawbwa, Sundadanio, Danio, Laubuca and Rasbora. The other includes those in which anatom...

Botia kubotaiPolka-Dot Loach
Botiidae · Kottelat, 2004
Appears to be endemic to headwaters of the Salween River basin around the border between Myanmar and Thailand. The type specimens were collected from the Megathat Chaung (Megathat stream) in the upper Ataran (known as the Kasat in Thai) River basin, Kayin/Karen State, Myanmar and another population was later discovered in the Hanthayaw River (Suriya in Thai), Tak Province, Thailand.

Brachydanio albolineataPearl 'Danio'
Cyprinidae · Blyth, 1860
Doubts remain whether B. albolineata is representative of a single species or a group of similarly-patterned, closely-related fish, and the form from Chantaburi province in eastern Thailand was revalidated as B. pulchra (formerly Danio pulcher Smith, 1931) by Kottelat (2013). The status of the currently invalid Danio tweedei (Brittan, 1955) from Kedah state, northern Peninsular Malaysia may also be in question, since fish from that area are clearly...

Brachydanio roseaRosy 'Danio'
Cyprinidae · Fang & Kottelat, 2000
B. rosea is a relatively recent addition to the aquarium trade but has proved very popular since it's colourful, hardy and usually quite cheap making it ideal for beginners. It's sometimes sold as 'purple passion danio'. It's very similar to B. albolineata sensu stricto but differs in several characters, notably the relatively slimmer body, shorter rostral barbels and lack of...

Brachygobius mekongensisMekong Bumblebee Goby
Gobiidae · Larson & Vidthayanon, 2000
Apparently restricted to slow-moving or standing freshwater habitats such as marshes, temporal swamps and floodplains where aquatic vegetation and submerged grasses proliferate. One locality consisted of undisturbed marshland with lightly tannin-stained water and dense growth of Vallisneria spp.

Brachygobius xanthomelas
Gobiidae · Herre, 1937
Type locality is '55 miles north of Singapore, freshwater ditches, Mawai District, Johore, Malaysia', and this species has been recorded throughout much of Peninsular Malaysia and southern Thailand. Records from Borneo and Singapore appear to be in error although it may have been extirpated from the latter but as with most members of the genus a degree of confusion surrounds its identity (see 'Notes').

Brevibora dorsiocellataEyespot Rasbora
Cyprinidae · Duncker, 1904
B. dorsiocellata is sometimes traded as 'green-eyed', 'emerald-eyed' or 'hi-spot' rasbora. There appear to exist several geographical forms of the species at least two of which have been seen in the trade. The most common is the rather plain-coloured fish that is produced commercially in large numbers and has gained popularity due to the bright green/blue reflective patch in the lower part of the eye.

Butis amboinensisOlive Flathead Gudgeon
Eleotridae · Bleeker, 1853
This species is not traded for aquaria but is occasionally exported as bycatch among shipments of other species. It differs from congeners in that the outermost row of teeth are not enlarged plus the interorbital space and cheek below eye are not scaled. Butis spp. are largely nocturnal ambush predators with cryptic...

Butis butisCrazy Fish
Eleotridae · Hamilton, 1822
Butis spp. are largely nocturnal ambush predators with cryptic patterning to help them blend in with their surroundings. They can also lighten and darken their body colouration to an extent, have a habit of aligning themselves with solid surfaces whether horizontal, vertical, or inverted, and often swim in an upside-down position. The genus is usually included in the family Eleotridae of which members are often referred to...

Carinotetraodon lortetiRedeye Puffer
Tetraodontidae · Tirant, 1885
Known from the lower Mekong basin in Thailand, Vietnam, and Cambodia, the Chao Phraya watershed in central Thailand, and may occur in smaller river systems between. Type locality is 'Thu-dâu-môt, Vietnam'.

Chagunius baileyi
Cyprinidae · Rainboth, 1986
There are currently three species which look almost identical and are most easily separated by collection details since their ranges do not overlap in nature; C. chagunio is endemic to the Ganges and Brahmaputra drainages and C. nicholsi to the Ayeyarwady/Irrawaddy.

Channa gachuaDwarf Snakehead
Channidae · Hamilton, 1822
Generally considered to have an enormous natural range extending from Iran to Taiwan and Bali, with records existing from Iran, Iraq, Afghanistan, Pakistan, Nepal, India, Sri Lanka, Bangladesh, Bhutan, China, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, Indonesia, and Singapore. However there exists significant evidence to suggest that C. gachua as currently understood represents a complex of similar-looking species, and a taxonomic review of the group is clearly required.

Channa luciusForest Snakehead
Channidae · Cuvier, 1831
Prefers a dimly-lit aquarium with plenty of cover in the form of live plants, driftwood branches, terracotta pipes, plant pots, etc., arranged to form a network of nooks, crannies, and shaded spots. Surface vegetation such as Ceratopteris spp. is also appreciated and makes the fish less inclined to conceal themselves.

Channa melasomaBlack Snakehead
Channidae · Bleeker, 1851
This species can be told apart from the similar-looking congener C. baramensis (once considered synonymous with C. melasoma) by absence (vs. presence) of a black spot in the centre of numerous body scales and absence (vs. presence in specimens larger than 120 mm SL) of a barred caudal-fin pattern.

Channa sp. 'fire and ice'
Channidae · authority not recorded
This unidentified species first appeared in the aquarium trade during 2009. It's easily told apart from similar-looking congeners by the patches of vivid red pigmentation surrounding the eye and sides of the mouth plus the thick, reddish, marginal band in the caudal-fin.

Crossocheilus atrilimesSiamese Algae Eater
Cyprinidae · Kottelat, 2000
This species is among a handful of near-identical congeners that are traded as 'Siamese algae-eater' (often abbreviated to 'SAE'), 'Siamese flying fox' and 'Crossocheilus siamensis'. The latter name is not valid, however, and is a synonym of Epalzeorhynchos siamensis which is itself a synonym of Crossocheilus oblongus, a species described from Java. C. oblongus is currently accepted to...

Crossocheilus langeiSiamese Algae Eater
Cyprinidae · Bleeker, 1860
C. oblongus is another name widely misused in the trade but that species has seemingly never been exported and was described as a blueish fish with yellow fins. It's native to streams of Gunung Salak mountain in Bogor Regency, West Java, Indonesia where collecting of ornamental fishes is almost non-existent. Other species of laterally-striped Crossocheilus also exist and may be available from time-to-time but are more easily told apart from the group described above.

Crossocheilus reticulatus
Cyprinidae · Fowler, 1934
While some laterally-striped members of the genus look very similar to one another the combination of silvery body, dark-edged scales and dark caudal peduncle blotch set C. reticulatus uniquely apart. The names Crossocheilus tchangi, Epalzeorhynchos coatesi and E. stigmaeus are all now considered synonyms of the species but were erected because the fish vary, most often in minor aspects of patt...

Cyclocheilichthys apogonBeardless Barb
Cyprinidae · Valenciennes, 1842
In the aquarium trade this species may also be seen on sale as 'skinhead barb'. As with others in the genus little has been written regarding its captive care but it makes a peaceful and unusual addition to larger aquaria. The best way of obtaining it may be to keep an eye on shipments of wild fishes from Indochina and the Greater Sunda Islands as it's rarely imported in large numbers and most often arrives as bycatch.

Cyclocheilichthys armatus
Cyprinidae · Valenciennes, 1842
It can be distinguished from congeners by possessing one or two pairs of barbels, a black blotch at the base of the caudal-fin, and rows of dark spots along the lateral scale rows. Members of Cyclocheilichthys are characterised by possessing a serrated dorsal fin spine, 9 branched pelvic fin rays, a conical snout, small, subterminal...

Cyclocheilichthys heteronema
Cyprinidae · Bleeker, 1854
This species is currently understood to have a considerable natural range extending eastwards from Myanmar via Thailand, Laos, Cambodia as far as Vietnam and to the south through Peninsular Malaysia and into the Greater Sunda Islands of Borneo and Sumatra. It thus occurs in the Mekong, Mae Klong and Chao Phraya drainages as well as a host of other river basins, lakes and reservoirs including the Tonlé Sap river...

Cyclocheilichthys lagleri
Cyprinidae · Sontirat, 1985
As with others in the genus little has been written regarding captive care of this species, but it makes a peaceful and unusual addition to larger aquaria. The best way of obtaining it may be to keep an eye on shipments of wild fishes from Indochina. It can be distinguished from congeners by possessing 20 circumpeduncular scales and lacking barbels entirely.

Cyclocheilichthys repasson
Cyprinidae · Bleeker, 1853
An ideal resident of the larger, well-furnished community set-up though it might upset slow-moving or timid companions simply by its size. There are plenty of suitable tankmates including many cyprinids, loaches, cichlids, catfish and characins, but as always when selecting a compatible community of fish proper research is essential. A community based around one of its native countries or river basins...

Datnioides polotaSilver Tiger Perch
Datnioididae · Hamilton, 1822
D. polota is sometimes referred to as D. quadrifasciatus (Sevastianov, 1809) but the original name of the latter, Chaetodon quadrifasciatus Sevastianov, 1809, is a junior primary homonym of the older Chaetodon quadrifasciatus Bloch & Schneider 1801, thus Coius polota Hamilton, 1822 takes precedence.

Datnioides undecimradiatusMekong Tiger Perch
Datnioididae · Roberts & Kottelat, 1994
An efficient, largely piscivorous, predator with highly protrusible mouthparts. In the aquarium, juveniles can be offered chironomid larvae (bloodworm), small earthworms, chopped prawn, and suchlike, while adults will accept strips of fish flesh, whole prawns, mussels, live river shrimp, larger earthworms, etc. Older individuals do not require feeding on a daily basis, with 2-3 times per week sufficient.

Desmopuntius johorensisStriped Barb
Cyprinidae · Duncker, 1904
D. johorensis can be distinguished by the following combination of characters: 5-6 dark, lateral stripes on body in specimens larger than 40 mm; stripes immediately above and below the central stripe (stripes '+1' and '-1', respectively) located on scale rows +2 and -2, not touching dorsal and ventral midlines (except in some small specimens from Peninsular Malaysia); stripes broad, typically between 0.5-1 scale rows deep...

Devario acrostomus
Cyprinidae · Fang & Kottelat, 1999
The type series was collected during the dry season from localities with varying gradient both within the Nam Leuk mainstream and smaller tributaries. In the tributaries the fish were found congregating in pools some of which were isolated on steep slopes. All habitats above Tad Leuk falls were characterised by clear to very clear water under forest cover while below the falls they were dominated by exposed basalt slabs with some underground water channels.

Devario chrysotaeniatus
Cyprinidae · Chu, 1981
This species is poorly known and first appeared in the hobby during 2005 but has rarely been seen since, probably because its natural waters lie outside the range of most commercial collectors. It can be distinguished by a combination of characters including: lateral line complete; infraorbital process absent; two pairs of short barbels; 8-9 branched dorsal fin rays; 12-13 branched anal fin rays; P stripe originating above pelvic fin and extending to en...

Devario laoensis
Cyprinidae · Pellegrin & Fang, 1940
It can be further distinguished from other species in the genus by colour pattern consisting of a dark, horizontal P stripe originating around mid-body, where it's relatively faint, this becoming thicker and darker in the posterior portion of the body and terminating at the base of the caudal-fin. Among congeners it's most similar to D. chrysotaeniatus but that species lacks the infraorbital process, has three rows of pharyngeal teeth and the P stripe extends to the end of the caudal-fin rays.

Devario reginaQueen 'Danio'
Cyprinidae · Fowler, 1934
Probably restricted to western and southern Thailand and northern Peninsular Malaysia plus some small surrounding islands. In Thailand records exist from Surat Thani (Ko Samui island), Nakhon Si Thammarat, Ranong, Trang, Phuket, Ratchaburi, Kanchanaburi, and Mae Hong Son provinces while in Peninsular Malaysia it's been collected from Perak and Kedah states, including th...

Discherodontus ashmeadi
Cyprinidae · Fowler, 1937
D. ashmeadi is the type species and exhibits differences in dental morphology compared with other members of the genus. It can also be told apart from D. halei by the red/pink (vs. orange) colouration in the dorsal and anal fins and serrated (vs. smooth) dorsal spine. D. schroederi is also similar-looking but as it matures the prominent dark dorsal blotch fades to a thin dark distal band whereas in D. ashmeadi it is retained throughout life.

Discherodontus halei
Cyprinidae · Duncker, 1904
Appears to have a disjunct range with records from Pahang state in central Peninsular Malaysia, plus the Mae Klong and Chao Phraya river systems in Thailand, but it has not been recorded in Peninsular Thailand. Type locality is 'Pahang River, Kuala Tembeling, eastern slope of Sangka Dua Pass, Malaysia, elevation about 2000 feet'.

Discherodontus schroederi
Cyprinidae · Smith, 1945
It's also been collected in more open areas but wherever it is found the substrate is composed of boulders, smaller stones, sand and/or gravel along with decomposing plant material. From images we've seen typical habitats are composed of short sections of rocky rapids interspersed by deeper pools with exposed bedrock. Rainboth describes how he collected a large group of...

Eirmotus octozona
Cyprinidae · Schultz, 1959
E. octozona can be told apart from congeners by the following combination of characters: bar 1 present; presence of a large and distinct black mark anterior to anus, visible in lateral and ventral views; simple dorsal-fin rays black, sometimes extending onto first branched ray; other rays hyaline or with diffused chromatophores on last dorsal-fin ray, adjacent to upper extremity of bar 6; 25-31 serrae on last simple dorsal-fin ray; uppermost ray of pectoral-fin with faint black margin; width of bar 5 equal to 1-1½ lat...

Epalzeorhynchos bicolorRed-Tailed Black Shark
Cyprinidae · Smith, 1931
Most members of Epalzeorhynchos were formerly regarded as Labeo spp. and are thus referred to as such in older literature. According to Rainboth (1996) they're characterised by absence of a dorsal spine, possession of 10-13 branched dorsal fin rays, a thin membrane connecting the upper and lower lips and rigid, freely moveable rostral lobes. Epalzeorhynchos itself has undergone some quite recent changes with a handful of species hav...

Epalzeorhynchos frenatumRainbow Shark
Cyprinidae · Fowler, 1934
The ornamental albino variant is widely-available and has become extremely popular in the hobby and there is a commercially-produced anerythristic (lacking red pigment) mutation that has pale yellowish fins and has sometimes been misidentified as E. munense. Also worthy of note is that the specific name is sometimes misspelled 'frenatus'. Most members of Epalzeorhynchos were formerly regarded as Labeo spp. and are thus referred to as such in older literature. According to Rainboth (1996) they're characterised by absence of a dorsal spine...

Epalzeorhynchos kalopterumFlying Fox
Cyprinidae · Bleeker, 1850
Confusion with similar-looking fishes from other genera, such as Garra cambodgiensis, laterally-striped Crossocheilus spp. or Gyrinocheilus aymonieri is not uncommon, and are largely attributable to the use of trade names such as 'false flying fox' or 'Siamese flying fox'. When compared with the other species E. kalopterus exhibits several unique characters but perhaps the simplest way to identify it is by the characteristic white-edged, red and black coloured fins and the presence of two pairs of barbels.

Epalzeorhynchos munense
Cyprinidae · Smith, 1934
This species does not appear to be in the aquarium hobby at time of writing though it may have been in the past, when exports of wild Epalzeorhynchos spp. still took place. Most members of the genus were formerly regarded as Labeo spp. and are thus referred to as such in older literature. According to Rainboth (1996) they're characterised by absence of a dorsal spine, possession of 10-13 branched dorsal fin rays, a thin membrane...

Esomus longimanusMekong Flying Barb
Cyprinidae · Lunel, 1881
Known from the Mekong river basin in Thailand, Laos, Cambodia, and Vietnam, the Tonlé Sap river and lake system in Cambodia, and smaller, coastal drainages in southeast Thailand. Records from Peninsular Malaysia are likely to refer to other species. Type locality is given simply as 'Cambodia'.

Esomus metallicusStriped Flying Barb
Cyprinidae · Ahl, 1923
There currently exist a dozen described Esomus spp. alhough few are seen in the aquarium trade and none are especially popular. Most are commonplace in their native countries and also quite plainly-patterned so generally overlooked by collectors. Their most common use in some areas is actually as a feeder fish in the aquaculture of larger species. They're characterised by greatly-enlarged pectoral fins and two pairs of barbels, of which the maxillary pair are extremely long and usually reach the pectoral fins.

Folifer brevifilis
Cyprinidae · Peters, 1881
This species is widely-distributed in the Mekong river system in Thailand, Laos, and Vietnam, Salween and Ayeyarwaddy rivers in southern China, Myanmar, and Thailand, plus various smaller basins in Vietnam and China. It has also been recorded from the islands of Hainan and Hong Kong. Type locality is given as 'China: sent from Hong Kong'.

Garra cambodgiensisFalse SAE
Cyprinidae · Tirant, 1883
Also known by the vernacular names ''black band garra', 'stone-lapping minnow' or 'false flying fox' and continues to be traded as Garra taeniata, an invalid name synonymous with G. cambodgiensis. It is often confused with those laterally-striped members of the genus Crossocheilus sold as 'Siamese algae eater' or 'Siamese flying fox', but in those species the dark lateral body stripe continues into the caudal-fin whereas in G. cambodgiensis it terminates...

Garra fasciacauda
Cyprinidae · Fowler, 1937
Native to the Mekong river system in Thailand, Laos, Vietnam, and Cambodia, including the Tonlé Sap basin. Type locality is 'Kemarat, Thailand', which corresponds to the Mekoong River in Khemmarat district, Ubon Ratchathani province, northeastern Thailand.

Garra sp. 'redtail'Burmese Red-tailed Garra
Cyprinidae · authority not recorded
A putatively undescribed species often imported and sold as G. sp. 'burmanicus'. It first appeared in the trade during 2005 and has since been available on a sporadic basis, usually with a relatively high price tag. As well as its unique colour pattern, a primary diagnostic character is the presence of a proboscis-like rostral process between the eyes.

Gymnothorax tile'Freshwater' Moray Eel
Muraenidae · Hamilton, 1822
Gymnothorax tile

Gyrinocheilus aymonieriSucking 'Loach'
Gyrinocheilidae · Tirant, 1883
This species is among the most well-known fishes in the aquarium trade but juveniles are typically being offered for sale with little to no information regarding temperament, eventual size, and potential age in excess of 15 years. Wild examples are not currently traded, with all of those seen on sale produced on a commercial basis.

Hampala disparSpotted Hampala Barb
Cyprinidae · Smith, 1934
The genus currently contains seven species of which H. macrolepidota and, to a lesser extent, H. dispar are the only ones seen with any regularity in the aquarium trade. As well as having the widest distribution H. macrolepidota is also the largest member of the group. All representatives can appear superficially similar at first glance, the exception being H. lopezi which is endemic to a single island in The Philippines and displays a unique lateral band-like marking on the flanks.

Hampala salweenensis
Cyprinidae · Doi & Taki, 1994
This species is poorly-known in the aquarium hobby and may have never been maintained outside its native countries. It can be distinguished from congeners by the following combination of characters: 26-27 lateral line scales; two roundish, dark blotches on each flank, one beneath dorsal-fin origin and above the lateral line, the other on the caudal peduncle and passing thro...

Helostoma temminkiiKissing Gourami
Helostomatidae · Cuvier, 1829
The pinkish-white form of this species is among the most widely-traded aquarium fishes in the world but does not occur naturally and is in fact a leucistic variant bred specifically for ornamental purposes. The 'short-bodied' or 'balloon' variety also continues to be fashionable but under no circumstances do we recommend the purchase of these intentionally disfigured animals which tend to have much shorter life spans than the naturally-shaped fish. There also exists a less-po...

Hemimyzon nanensis
Balitoridae · Doi & Kottelat, 1998
Most importantly the water must be clean and well-oxygenated so we suggest the use of an over-sized filter as a minimum requirement. Turnover should ideally be 10-15 times per hour so additional powerheads, airstones, etc. should also be employed as necessary. Base substr...

Homaloptera bilineata
Balitoridae · Blyth, 1860
This rarely-traded species is a member of the H. ocellata 'group' of closely-related congeners, an assemblage which currently comprises H. ocellata, H. bilineata, H. confuzona, H. orthogoniata, H. ogilviei and H. parclitella. Following Tan and Ng (2005) these share possession of a colour pattern with reddish tints and dark brown head markings, elongate head, slightly compressed body, 61-77 lateral line scales and dorsal-fin origin placed in advance of pelvic-fin origin.

Homaloptera confuzona
Balitoridae · Kottelat, 2000
Most records pertain to the Mekong River basin downstream of the Khone waterfalls in Laos and Cambodia, but this species is also known from some smaller river drainages in southern Thailand, including parts of the Mae Klong system. Type locality is 'Khlong Fit at Ban Kraduk Chang, road 3157 from Trat to borai, about 2-3 kilometers after junction w...

Homaloptera ogilviei
Balitoridae · Alfred, 1967
The reason that the paired fins are orientated vertically, as opposed to horizontally in other members of the genus, is unclear but Roberts (1989) suggest it may be an adaptation to this species' ecology, in that it displays a preference for submerged vegetation or woody structures as opposed to rocky environments. They're certainly adapted for a rea...

Homaloptera parclitella
Balitoridae · Tan & Ng, 2005
The water at the type locality is described as 'clear and fast-flowing over a rocky substratum'. H. parclitella was observed in shallow water among the rocks, and sympatric species included Garra cambodgiensis, Neolissochilus soroides, Poropuntius smedleyi, 'Puntius' binotatus, Homaloptera nebulosa and Amblyceps mangois.

Homalopteroides modestus
Balitoridae · Vinciguerra, 1890
Homalopteroides spp. are specialised micropredators feeding on small crustaceans, insect larvae and other invertebrates. In captivity some sinking dried foods may be accepted but regular meals of live or frozen Daphnia, Artemia, bloodworm, etc., are essential for the maintenance of good health.

Homalopteroides smithi
Balitoridae · Hora, 1932
Described from close to the village of Ban Khiri Wong, Nakhon Si Thammarat Province, southern (peninsular) Thailand but since recorded throughout much of the country, including the Chao Phraya and Mekong river systems. It's also known from Peninsular Malaysia and parts of the Mekong basin in Laos, Cambodia and Vietnam. Rainboth (1996) considered it 'probably the commonest member of the genus in the Mekong' and in a 2008 study of balitorid habitats in centra...

Homalopteroides tweediei
Balitoridae · Herre, 1940
Described from Kota Tinggi district, Johor state, Peninsular Malaysia but since recorded throughout much of the country as well as parts of the the Mekong river system in Thailand, Laos, Cambodia and Vietnam plus the Kapuas and several other river basins in Kalimantan Barat (West Kalimantan) province, Indonesian Borneo. In the Kahang River, part of the Endau drainage in Jo...

Hypsibarbus lagleri
Cyprinidae · Rainboth, 1996
This species is migratory on a seasonal basis; during the dry season it can be found in larger river channels, whereas during drier months it moves into smaller tributaries and flooded forests. Apparently displays a preference for rocky habitats and is not known to adapt to reservoirs or other artificial impoundments.

Hypsibarbus vernayi
Cyprinidae · Norman, 1925
It is very similar to H. wetmorei but can be told apart by possessing yellow (vs. orange to red in H. wetmorei) pectoral, pelvic, and anal fins. It thus appears likely that yellow-finned fish marketed as H. wetmorei or 'lemon fin barb' in the ornamental trade are actually H. vernayi, with both species available on a regular basis.

Hypsibarbus wetmorei
Cyprinidae · Smith, 1931
H. wetmorei is distinguished from congeners by the following combination of characters: upper body reddish brown; robust body, not compressed; usually 4½ scale rows between lateral line and dorsal-fin origin; 8-12 rakers on first gill arch; 7-9 predorsal scales; 14 circumpeduncular scale rows; usually two scale rows separating vent and anal-fin; <29 lateral line scales; 9-14 serrations on the spinous dorsal-fin ray; distance between distal serrae on posterior margin of last unbranched dorsal-fin ray much greater than the width of their bases.

Indostomus crocodilus
Indostomidae · Britz & Kottelat, 1999
The type series was collected from a blackwater stream in Toh Daeng Peat swamp forest with the fish found in slow-moving or standing habitats among submerged shoreline roots and leaf litter. In the Tapi River floodplain it was collected from stagnant waters, one of which was an oxbow lake approximately 200 m long and 30 m across at its widest point, surrounded by 'freshwater scrub and swamp trees'. The substrate was composed of mud, woody structures including fallen twigs and branches, and decomposing plant material.

'Inlecypris' maetaengensisFire Bar 'Danio'
Cyprinidae · Fang, 1997
A peaceful species suited to a well-chosen community aquarium. There are plenty of potential tankmates including many cyprinids, loaches, cichlids, catfishes and characins, although as always proper research is essential in order to avoid problems.

Kryptopterus bicirrhis
Siluridae · Valenciennes, 1840
Generally peaceful though it may predate on smaller fishes and is somewhat timid so does not compete well with much larger, robust or otherwise boisterous species. Peaceful, comparably-sized cyprinids, loaches and other catfishes perhaps constitute the best options but be sure to research your choices thoroughly prior to purchase.

Kryptopterus geminus
Siluridae · Ng, 2003
This species is likely to be traded for aquaria but probably misidentified as the very similar-looking K. cyrptopterus with which wild populations were formerly considered conspecific. These two are closely-related and can be distinguished from congeners by the dorsal profile lacking a nuchal concavity (vs. possessing a nuchal concavity) and possessing short maxillary barbels (extending to the pectoral-fin base vs. ext...

Kryptopterus limpok
Siluridae · Bleeker, 1852
Type locality is 'Palembang, Sumatra, Indonesia', but this species is widely-distributed throughout much of Southeast Asia including major river systems in Thailand, Laos, Cambodia, Vietnam and Peninsular Malaysia plus the Greater Sunda Islands of Sumatra, Borneo and Java. It's been extensively recorded from the Mekong, Cha...

Kryptopterus macrocephalusStriped Glass Catfish
Siluridae · Bleeker, 1858
Has been recorded in fast-flowing environments but most commonly associated with peat swamp forests and associated blackwater streams. Many such habitats have suffered degradation of some kind but in unaltered cases the dense canopy of branches above means very little light penetrates the surface of such environments, and riparian vegetation also tends to grow thickly.

Kryptopterus vitreolusGlass Catfish
Siluridae · Ng & Kottelat, 2013
This species has been available in the trade for decades during which time it's been widely misidentified as the valid congeners K. bicirrhis or, more recently, K. minor. Its identity was not resolved until early 2013 meaning you will find it under one of these two names in the majority of literature published prior to that date. Other trade names include 'Asia...

Labiobarbus leptocheilus
Cyprinidae · Valenciennes, 1842
Different populations vary in appearance somewhat (see image of Salween specimen for example), and L. leptocheilus may turn out to represent a group of closely-related species rather than a single taxon. The population from the Cambodian Mekong has been considered to represent a distinct species, Labiobarbus lineatus, although that name is currently a synonym of L. leptocheilus following Kottelat (2013). It is widely used in the ornamental trade, however.

Laubuka caeruleostigmataFlying Minnow
Cyprinidae · Smith, 1931
This species is also known as 'leaping barb' and was once quite common in the ornamental trade but is now seldom seen. It can be distinguished from other members of the genus by the following characters: bright blue spot on top of head; series of 4-5 short faint bars on anterior portion of body; 19-23½ branched anal-fin rays; body depth fits 2.1-2.9 times in SL.

Laubuka siamensis
Cyprinidae · Fowler, 1939
Considered synonymous with the congener L. laubuca for a number of years, thus reports of that species from anywhere in Indochina actually refer to the current concept of L. siamensis. Given the distribution of L. siamensis, it seems likely that many of the fish entering the aquarium trade are also this species and not L. laubuca. The two species can be distinguished by...

Lepidocephalichthys berdmorei
Cobitidae · Blyth, 1860
This is one of the most frequently-traded members of the genus and is an excellent choice for those new to keeping loaches. It's distinguishable from congeners by a combination of characters including: relatively large adult size (to at least 80 mm SL); rounded/truncate caud...

Lepidocephalichthys furcatus
Cobitidae · de Beaufort, 1933
This species is not traded often but is occasionally available as bycatch among shipments of other species. It can be told apart from congeners most easily by the prominent, dorsally-orientated, roughly semi-circular lamina circularis in males, a feature unique within the genus. Other distinguishing characters include a combination of: forked caudal-fin; relatively small adult size; dark <-shaped mark at the base of the caudal-fin; a black spot at the base of branched caudal-fin rays 3-5.

Lepidocephalichthys hasselti
Cobitidae · Valenciennes, 1846
At one locality close to Ban Na Hwai, Chiang Mai Province, Thailand L. hasselti was collected from a shallow (<0.5 m) pool in a swampy zone between forest and rice fields. The substrate was of mud, there was no aquatic vegetation and it was being used as drinking water by local animals, with the only effluent connected to a 'small creek'. Other species found there were Physoschistura pseudobrunneana, Rasbora hobelmani and Systomus cf. orphoides.

Lepidocephalichthys kranos
Cobitidae · Havird & Page, 2010
The family Cobitidae, often referred to as 'true' loaches, is widely-distributed across most of Eurasia with the Indian subcontinent, Southeast Asia and China representing particular centres of species diversity. Phylogenetic analyses by Tang et al. (2006), Šlechtová et al. (2007) and Šlechtová et a...

Lepidocephalichthys micropogon
Cobitidae · Blyth, 1860
According to Kottelat (2012) L. manipurensis Arunkumar, 2000, which was described from Moreh, Manipur state, northeastern India, close to the border with Myanmar, is a syonym of L. micropogon. Havird and Page (2010) differentiate the two based on caudal-fin patterning, predorsal length and ver...

Lepidocephalichthys zeppelini
Cobitidae · Havird & Tangjitjaroen, 2010
The type locality consisted of remnant ephemeral pools in otherwise dry agricultural land, and many adults were collected from such habitats. Other species present included the congener L. hasselti plus members of Anabas, 'Puntius', Rasbora, Channa, and Hampala.

Lepidocephalus macrochir
Cobitidae · Bleeker, 1854
The distribution records for this species are somewhat confusing. It was described from the confluence of the Lamatang and Enim rivers, Palambang Province, Sumatra and has since been recorded from Thailand (Chao Phraya River), Peninsular Malaysia (Pahang River) plus the islands of Java (Solo River) and Borneo (Kapuas and Barito rivers).

Lobocheilos melanotaenia
Cyprinidae · Fowler, 1935
The majority of Lobocheilos species are endemic to the Greater Sunda Islands of Borneo, Sumatra, and Java, and are uncommon in the aquarium trade, but the widespread Indochinese taxa L. melanotaenia and L. rhabdoura are available on a sporadic basis. L. melanotaenia can be distinguished from L. rhabdoura by the following comb...

Lobocheilos rhabdoura
Cyprinidae · Fowler, 1934
Lobocheilos species are specialised grazers of periphyton, benthic algae, and other organisms which grow attached to rocks and other solid surfaces, and they typically leave visible scrape marks in places where they have been feeding. They are by no means herbivorous and should be offered meaty foods such as live or frozen chironomid larvae (bloodworm), Tubifex, Artemia, chopped prawn, etc., along with good quality, sinking dried products, at lea...

Luciosoma bleekeri
Cyprinidae · Steindachner, 1878
L. bleekeri is most-easily distinguished from the congener L. setigerum, with which it is frequently confused, by absence (vs. presence) of a series of black spots on the lateral line scales.

Luciosoma setigerumApollo Shark
Cyprinidae · Valenciennes, 1842
There is a fish of unknown geographical origin which matches the majority of diagnostic features for L. setigerum with the exception that the dark lateral stripe is absent in the anterior portion of the body and is not composed of interconnected spots. It is relatively common in the aquarium trade and included here as L. cf. setigerum until a confirmed identity is established.

Microdevario kubotai
Cyprinidae · Kottelat & Witte, 1999
Apparently inhabits calm to moderately-flowing stretches of well-oxygenated headwaters and minor tributaries. Such habitats tend to comprise transparent water, substrates of sand, gravel, rocks, boulders, and patches of leaf litter, with submerged driftwood, roots of riparian vegetation, and aquatic vegetation in places.

Mystacoleucus argenteus
Cyprinidae · Day, 1888
All Mystacoleucus species possess a procumbent predorsal spine orientated towards the head, though it can be difficult to spot with the naked eye. This can become entangled in an aquarium net so care must be taken when handling the fish. The trait is shared by members of Tor, Spinibarbus and Paraspinibarbus although there exists no strong evidence to suggest that these genera form a monophyletic lineage and it is...

Mystacoleucus greenwayi
Cyprinidae · Pellegrin & Fang, 1940
Predominantly a riverine fish favouring clear, well-oxygenated, running water with substrates of sand or gravel and often present in rock and boulder-filled headwater streams. In the Mun River, close to the Pak Mun dam, Thailand, sympatric species included Hampala dispar, Cyclocheilichthys apogon, Osteochilus hasseltii,...

Mystacoleucus obtusirostris
Cyprinidae · Valenciennes, 1842
This species is occasionally marketed as 'Burmese Rainbow Barb' in the ornamental trade. others may have been exported in small numbers or as bycatch among shipments of other species. It was referred to as Mystacoleucus marginatus for decades, but that name is a simultaneous subjective synonym of M. obtusirostris following Kottelat (2013).

Nemacheilus binotatus
Nemacheilidae · Smith, 1933
N. binotatus is distinguished from similar-looking congeners such as N. longistriatus and N. ornatus by its unique body patterning consisting very simply of two dark stripes, one running along the dorsal surface and the other from the tip of the snout, through the eye and along the flank. There are usually 1-3 small, vertically-orientated spots extending above the lateral stripe between the pectoral-fin and dorsal fins. These are su...

Nemacheilus longistriatusLaos Blackline Torpedo Loach
Nemacheilidae · Kottelat, 1990
Fishes which inhabit similar biotopes in nature constitute the best options, especially peaceful, open water-dwelling cyprinids since the presence of one or two schools can make a visible difference to the confidence of this naturally reclusive loach. Other possibilities include rheoph...

Nemacheilus masyaeArrow Loach
Nemacheilidae · Smith, 1933
This species was originally named Nemacheilus masyae but following ICZN rules the spelling was later corrected to N. masyai because it's named after a man. It can be distinguished from the majority of congeners by body patterning comprising 14-18 short, dark vertical bars on each flank, 12-17 saddle-like markings running along the dorsal surface, a dark spot on the caudal peduncle at the termination of the lateral line and a dark blotch in the lower half of the first few dorsal-fin rays.

Nemacheilus ornatus
Nemacheilidae · Kottelat, 1990
This species is distinguished from similar-looking congeners such as N. longistriatus and N. ornatus by its unique colour pattern consisting of a black lateral body stripe with 9-16 vertically-orientated blotches extending along it both above and below, plus an irregular stripe running along the dorsal surface. The anterior lateral blotch is surrounded by lighter pigment, forming an ocellus similar to that seen in N. binotatus.

Nemacheilus pallidus
Nemacheilidae · Kottelat, 1990
The similar-looking N. masyai is sometimes traded as N. pallidus, but the two can be told apart by body depth (14.8-19.1 % in N. pallidus vs. 12.6-17.6 % SL in N. masyai), interorbital width (5.7-8.0 % vs. 4.9-6.8 % SL) and the fact that in N. pallidus the dark body bars and saddles are thinner than the light-coloured interspaces between (vs. wider in N. masyai).

Nemacheilus platiceps
Nemacheilidae · Kottelat, 1990
This species is only traded occasionally. It's distinguished from congeners by a combination of characters including: 12-16 dark, irregular, vertical bars on body, usually split vertically; lips without furrows; inco...

Nemacheilus selangoricus
Nemacheilidae · Duncker, 1904
N. selangoricus is most similar to N. spiniferus since it possesses acuminate scales above and below the lateral line on the caudal peduncle, a feature not shared with any other congener. It can however be distinguished by the following characters: presence of 8-12 very regular dark bars on flanks (vs. 10-13 irregularly-shaped bars in N. spiniferus), 3-5 times...

Opsarius bernatziki
Cyprinidae · Koumans, 1937
Type locality is ' Kapa, northwestern peninsular Thailand', which may refer to modern-day Kapoe district, Ranong province, and additional records exist from other localities in Ranong as well as Phang-nga and Pattani provinces. Although the precise extent of its distribution is unclear it appears to occur in river systems on both sides of the Tennaserim Hills in pen...

Opsarius caudiocellatus
Cyprinidae · Chu, 1984
This species may have appeared in the aquarium trade though probably not under the correct name. It can be told apart from similar-looking congeners by the following combination of characters: presence of a black round spot at the caudal base; dorsal-fin rays black with connecting membranes transparent; posterior dorsal-fin origin located midway between upper angle of gill aperture and caudal-fin base, or slightly closer to the latter.

Opsarius infrafasciatus
Cyprinidae · Fowler, 1934
This species has previously been considered synonymous with both O. ornatus and O. pulchellus but is currently considered to be distinct following (Tejavej, 2012). It can be distinguished from congeners by a combination of characters including: small caudal spot presen...

Opsarius koratensis
Cyprinidae · Smith, 1931
Inhabits well-oxygenated, low-to-medium gradient, slow to moderate-flowing rivers and streams with substrates of gravel, cobbles, larger boulders and exposed bedrock. At the habitat in our image pH was 7.5, temperature 26°C and cond...

Opsarius ornatus
Cyprinidae · Sauvage, 1883
Type locality is 'Mé-Nam River, Thailand', with 'Mé-Nam' having been considered an older name for the Chao Phraya river in central and western Thailand prior to this species' redescription by Tejavej (2012). In fact 'menam' is the Thai word for 'river' and thus could refer to any drainage, and B. ornatus is restricted to...

Opsarius pulchellus
Cyprinidae · Smith, 1931
This species is traded for aquaria under various names including 'butterfly barb', 'mackerel barb', 'green-barred danio', and 'royal opsarius'. It can be told apart from other memb...

Opsarius signicaudus
Cyprinidae · Tejavej, 2012
O. dogarsinghi and O. bernatziki are the only two Southeast Asian congeners to possess a large blotch at the caudal-fin base but in the former the blotch is vertically-orientated and hardly extends onto the fin itself (vs. laterally-elongate and extending onto the basal fin rays) and long (vs. short) barbels, while th...

Oryzias dancenaIndian Ricefish
Adrianichthyidae · Hamilton, 1822
This species continues to be mislabelled as O. melastigma, a name currently considered invalid by the majority of recent workers, or O. javanicus, a valid but distinct taxon. Roberts (1998) demonstrated that MClelland's description of Aplocheilus melastigmus, later renamed O. melastigma, does not correspond with any known Oryzias species from the Indian subcontinent or Myanmar since it's said to have a dark spot in the dorsal-fin and an excessively slim body, among other anomalies.

Oryzias javanicusJavanese Ricefish
Adrianichthyidae · Bleeker, 1854
This species is widely-distributed throughout Peninsular Thailand, Malaysia (Malay Peninsula plus the states of Sabah and Sarawak, Borneo), Singapore and Indonesia, with records from the Riau Archipelago, Sumatra, Java, Borneo, Bali, Lombok, and Sulawesi existing in the latter. Type locality is 'Panimbang River, Perdana, Indonesia'. It's typically found in coastal, normally brac...

Oryzias mekongensisMekong Ricefish
Adrianichthyidae · Uwa & Magtoon, 1986
It can be further distinguished from congeners by the following combination of characters: small adult size; bright orange-red marginal bands on caudal-fin lobes in males; caudal-fin rounded and elongate; 5-7 dorsal-fin rays; relatively few (13-18) anal-fin rays without bony contact organs, the last ray branched; 6-8 pectoral-fin rays. Members of the family Adrianichthyidae are...

Oryzias minutillusDwarf Medaka
Adrianichthyidae · Smith, 1945
Best maintained in a heavily planted set-up, ideally with a dark substrate, patches of dense vegetation, and some open areas. Other décor can consist of twisted roots and pieces of bogwood, while surface vegetation is also appreciated by the fish. When maintained under such conditions they're more likely to display their best colours, and planted aquaria also offer fry a more favourable chance of survival alongside the adults.

Oryzias songkhramensis
Adrianichthyidae · Magtoon, 2010
An exclusive inhabitant of fresh, normally standing, waters including shallow pools, ditches, rice paddies and clear water swamps. The type locality is a small ditch measuring just 3 - 6 metres in width and 0.5 - 2 metres deep. The water was clear and the substrate composed of sand, detritus and mud with growths of the macrophytes Nymphaea lotus, Jussiaea repens and Hydrilla verticillata.

Pangio anguillaris
Cobitidae · Vaillant, 1902
One of a handful of Pangio spp. traded under the generic name 'eel loach'. Wild populations tend to differ in colour pattern to some extent, with some exhibiting a more intense lateral stripe while others display an irregular pattern of fine dark spots on the body, for example.

Pangio cuneovirgata
Cobitidae · Raut, 1957
Infrequently encountered in the aquarium trade, most often as bycatch among shipments of similar-looking congeners. It's included in the P. kuhlii group of closely-related species within the genus, and can be distinguished from other members by...

Pangio myersiGiant Kuhli Loach
Cobitidae · Harry, 1949
It's included in the P. kuhlii group of closely-related species and can be distinguished from other members by the following combination of characters: 8-11 very broad, quadrangular, regular dark body bars; orange base body colour; caudal-fin either entirely black or with a large black blotch at the base and a submarginal dark bar or row of spots. The latter feature can be useful in identifying young or newly-imported, undernourished specimens which can...

Pangio oblongaBlack Kuhli Loach
Cobitidae · Valenciennes, 1846
Described from close to the city of Bogor, Jawa Barat (West Java) province on the island of Java, Indonesia, but currently considered widespread with recorded occurrences on Java, Sumatra, Borneo and mainland Peninsular Malaysia. Some populations exhibit lighter...

Paracanthocobitis botiaZipper Loach
Nemacheilidae · Hamilton, 1822
Traded under various names including 'mottled', 'eyepot', 'sand' and 'striped' loach. It's perhaps one of the better choices for those new to keeping nemacheilids being relatively hardy, peaceful and exhibiting some quirky behavioural traits. The characteristic ocellus, a dark marking at the top of the caudal peduncle that resembles an eye, is thought to have some function in predator distraction and is normally more intense in younger specimens.

Paracanthocobitis pictilisCherry-fin Loach
Nemacheilidae · Kottelat, 2012
Prior to description this species was considered to represent, and traded as, A. rubidipinnis, but that species is apparently endemic to the lower Irrawaddy basin in Myanmar and unknown in the aquarium hobby. Male individuals of A. pictilis, A. botia and A. mandalaysensis possess a suborbital slit rather than suborbital flap which immediately distinguishes...

Paracanthocobitis zonalternans
Nemacheilidae · Blyth, 1860
According to Kottelat (1990) the chief distinguishing characters for the genus are: possession of 9-18½ branched dorsal-fin rays; colour pattern without black basal caudal bar, but with an ocellus at upper base of caudal-fin; upper lip with or without several rows of papillae; lower lip with a broad median interruption and a widened, papillated pad on each side.

Pethia stoliczkana
Cyprinidae · Day, 1871
This species is confused with P. ticto in much of the available literature and is sometimes listed as a synonym of it. Although some populations of the two species possess a similar colour pattern (there are reports of a P. ticto variant from the south of West Bengal state in India with a red, black-flecked dorsal-fin, for example) they do not occur in the same waters in nature and can be distinguished by examining the lateral line. This is complete in...

Pseudohomaloptera leonardi
Balitoridae · Hora, 1941
Type locality is given as 'Kuala Tahan, Pahang (King George V National Park)' which corresponds to the village of Kuala Tahan in Pahang state, central Peninsular Malaysia. The settlement is located at the confluence of the Tahan and Tembiling Rivers which form part of the Pahang river basin, while the national park was re...

Pseudohomaloptera sexmaculata
Balitoridae · Fowler, 1934
H. sexmaculata is very similar to H. leonardi but can be told apart since it possesses 2 simple and 12-14 branched pectoral-fin rays (versus 6 simple and 11 branched rays). Both of these species are sometimes misidentified as H. yunnanensis which has 7 simple and 12 branched pectoral-fin rays.

Puntigrus partipentazona
Cyprinidae · Fowler, 1934
Recorded from numerous river basins in Vietnam, Cambodia, Laos, Thailand, and Peninsular Malaysia, including the Mekong, Chao Phraya, Mae Khlong, Chanthaburi, Tapi, Golok, Terengganu, Pahang, Endau, and Muar. Type locality is 'Kratt, southeastern Siam', which corresponds to modern-day Trat Province, Thailand.

Puntius cholaSwamp Barb
Cyprinidae · Hamilton, 1822
P. chola was retained in Puntius sensu stricto, of which members are defined by the following combination of characters: adult size usually less than 120 mm SL; maxillary barbels absent or present; rostral barbels absent; 3-4 unbranched and 8 branched dorsal-fin rays; 3 unbranched and 5 branched anal-fin rays; last unbranched dorsal-fin ray weak or strong and unserrated; lateral line complete with 22-28 pored body scales...

Rasbora dorsinotata
Cyprinidae · Kottelat, 1987
Type locality is 'Mae Nam Huey Bon, kilometer 45 on road from Amphoe ThaWang Pha to Amphoe Chiang Kham, Chiang Rai Province, Thailand', and this species appears restricted to the Mekong and upper Chao Phraya river basins in northern Thailand and northern Laos. The specimens pictured here were collected from th...

Rhinogobius chiengmaiensisChiangmai Stream Goby
Gobiidae · Fowler, 1934
This species has been exported for the ornamental trade but often labelled as the congener R. mekongianus. Although the two do appear relatively similar R. chiengmaiensis can be identified by a combination of external characters including: presence of 5 irregular dark markings on the body (vs. 7-8 i...

Rhinogobius mekongianus
Gobiidae · Pellegrin & Fang, 1940
Known from various parts of the middle and upper Mekong river basins with record existing from the Nam Tha, Nam Ou, Nam Khan, Nam Lik, Nam Ngum and Nam Mang tributary systems in Laos, the Nam Noeua (a tributary of Nam Ou) in Vietnam, and the Mae Nam Kok in Thailand. Occurrences in the Chao Phraya drainage in central Thailand most likely refer to the congener R. chiengmaiensis.

Schistura alticrista
Nemacheilidae · Kottelat, 1990
This species is very rare in the aquarium trade but available on occasion. It has 8-9 darkish body bars which usually split vertically as the fish mature, and like some conspecifics possesses a prominent dorsal adipose crest on the caudal peduncle. Schistura is the most species-rich genus among...

Schistura aurantiaca
Nemacheilidae · Plongsesthee, Page & Beamish, 2011
During collections of the type series stream width was found to vary seasonally but was never wider than 9.1 metres. Water depth was 10-40 cm, flow rate 20-70 cm/s−1, and substrates comprised small to medium-sized rocks. Water temperature was seasonally variable but always within the range 20-26°C/68-78.8°F, pH was 6.5-7.9, oxygen 7.4-8.5 mg/l−1, ammonia, nitrate and total iron were 0.01, < 0.03 and < 0.5 mg/l−1, respectively, and alkalinity was aro...

Schistura balteataSumo Loach
Nemacheilidae · Rendahl, 1948
This species is quite uncommon in the aquarium hobby although its name is sometimes used in reference to the similar-looking, apparently undescribed congener S. cf. balteata, and both are also traded as 'sumo loach', 'tri-banded sumo loach', and 'orange saddle-back loach'. Following Kottelat (1990) it's diagnosed by the following combination of characters: unique colour pattern consisting of two da...

Schistura cf. balteataSumo Loach II
Nemacheilidae · authority not recorded
This apparently undescribed species has been available in the hobby since around 2006 and has been traded under several trade names of which others include 'tri-band sumo loach' and 'chubby loach'. The name 'Sumo II' is now in wide use to distinguish it from the real S. balteata since both have been traded as 'Sumo loach'...

Schistura geisleri
Nemacheilidae · Kottelat, 1990
Fishes which inhabit similar biotopes in nature constitute the best options, especially peaceful, open water-dwelling cyprinids since the presence of one or two schools can make a visible difference to the confidence of this naturally reclusive loach.

Schistura kengtungensis
Nemacheilidae · Fowler, 1936
This species is distributed in the middle Mekong River basin in north and northeastern Thailand, Myanmar and Xishuangbanna Dai Autonomous Prefecture, Yunnan province, southern China, and is also known from the Nam Beng, Nam Tha and Nam Yuoan drainages in Laos. Type locality is 'Laun We (Loi Mw...

Schistura kohchangensisOrnate Tiger Sand Loach
Nemacheilidae · Smith, 1933
On Koh Chang one habitat consisted of a stream flowing from the waterfall Nam Tok Mai Yom which empties into the Gulf of Thailand after less than 1 km. The stream was dry in its lower reaches and had a substrate of boulders and pebbles. Sympatric fi...

Schistura maepaiensis
Nemacheilidae · Kottelat, 1990
The type locality originally consisted of a shallow (0.5 - 1.5 m deep) stream with a substrate of rocks and boulders and flow varying from 'moderate to swift'. When the holotype was collected there in 1980 sympatric species included Acanthocobitis zonalternans, Puntius orphoides, Pethia ticto, Raiamas guttatus, Barilius barnoides, Mystacoleucus argenteus and Mastacembelus armatus plus unidentified members of Crossocheilus an...

Schistura nicholsi
Nemacheilidae · Smith, 1933
This species is sometimes traded for aquaria but its name also appears to have been widely misapplied to other fishes. It can be identified via the following combination of characters: presence of 8-10 quite regular dark bars...

Schistura pridiiMini Dragon Loach
Nemacheilidae · Vidthayanon, 2003
Endemic to a handful of tributary streams within the upper Chao Phraya river system in northern Thailand. Six populations are known to date, with the majority lying inside the Doi Chiang Dao Wildlife Sanctuary. Some of its habitats are under threat by over-grazing, deforestation, deliberate forest fires, and collection for the aquarium trade.

Schistura robertsi
Nemacheilidae · Kottelat, 1990
Should not prove difficult to maintain under the correct conditions. We strongly recommend keeping it in a tank designed to resemble a flowing stream or river with a substrate of variably-sized rocks, sand, fine gravel, and some water-worn boulders. This can be further furnished wit...

Schistura schultzi
Nemacheilidae · Smith, 1945
There appears to be some discrepancy between Smith's original description and Kottelat (1990) in that Smith states the fish is a member of a group of species lacking an ocellus at the upper caudal-fin base, whereas Kottelat mentions the presence of 'a black spot at upper extremity of caudal-fin base, surrounded by a whitish area'.

Schistura spilota
Nemacheilidae · Fowler, 1934
Not a commonly species in the aquarium hobby but sporadically available in shipments of wild fishes from Thailand. Following Kottelat (1990) it's a member of a group of species possessing a complete or near-complete lateral line, 8 ½ branched dorsal-fin rays, 17 branched caudal-fin rays and lacking sexual dimorphism (the latter is not strictly true - see above). Its colour pattern is quite distinctive, howe...

Serpenticobitis zonata
Serpenticobitidae · Kottelat, 1998
Fish sold under the name S. zonata are sporadically available in the aquarium trade but the majority appear to be the congener S. octozona. The genus currently contains just three members all of which are known only from the Mekong basin. S. octozona is the type species and separ...

Syncrossus beaufortiChameleon Loach
Botiidae · Smith, 1931
This species is very similar in appearance to S. berdmorei which is native to India and Myanmar, and has been widely mislabelled under that name in older aquarium literature. The two can appear identical on first glance but there are some notable differences, most obviously possession of 9-10 branchedrays in S. beauforti vs. 11-14 in S. bermorei, and the fact that even young specimens of S. beauforti exhibit laterally-orientated rows of small, dark markings running across the ...

Syncrossus helodesBanded Tiger Loach
Botiidae · Sauvage, 1876
This species is sometimes confused with S. hymenophysa, native to the Greater Sunda Islands and Peninsular Malaysia, but differs in several ways, the most immediately identifiable of which are possession of small, irregular, dark markings in the lower half of the body and lack of a dark spot in the dorsal-fin. It also has 10-12 vertical body bars...

Systomus orphoides
Cyprinidae · Valenciennes, 1842
The genus Puntius is currently viewed as something of a catch-all for well over 100 species of small to mid-sized cyprinid. Most experts agree that a full revision is required with the likely outcome that many species will be placed into new or different genera since it is clearly polyphyletic. When describing the grouping in 1822 Hamilton identified the defining characteristics as: presence or absence o...

Trichopsis pumilaSparkling Gourami
Osphronemidae · Arnold, 1936
It can be distinguished from congeners by its small adult size and presence of a single solid dark midlateral stripe on the body, above which is a series of dark blotches forming a second stripe. In the similar but larger, T. schalleri the upper stripe is more variable depending on the mood of the fish, sometimes fading entirely.

Trichopsis schalleri
Osphronemidae · Ladiges, 1962
Known from the lower Mekong River basin in Laos, Thailand, Cambodia, and Vietnam, plus tributaries of the Chao Phraya watershed in central Thailand, and drainages between the Chao Phraya and Mekong in eastern Thailand. Type locality is 'Nam-Mun at Korat, 135 miles northeast of Bangkok, Thailand'.

Trichopsis vittataCroaking gourami
Osphronemidae · Cuvier, in Cuvier & Valenciennes, 1831
The common name is derived from the ability of genus members to produce audible sounds via a specialised pectoral mechanism which is unique within the family Osphronemidae. The structure comprises modified pectoral-fin tendons and muscles which are stretched and plucked by basal elevations of two fin rays in a similar way to guitar strings via rapid beating of the fins. The pectoral-fins beat alternately, each able to generate short or long bursts of sound. These sounds are produced by both sexes, predom...

Trigonostigma espeiLambchop Rasbora
Cyprinidae · Meinken, 1967
This species is very peaceful indeed making it an ideal resident of the well-maintained community tank. As it places no extreme demands in terms of water chemistry it can be combined with many of the most popular fish in the hobby including other small cyprinids as well as tetras, livebearers, dwarf cichlids, catfishes, and loaches. As always when selecting a compatible community of fish thorough research is essential and its small adult size must be a consideration, however.

Trigonostigma heteromorphaHarlequin
Cyprinidae · Duncker, 1904
T. heteromorpha was first exported for aquaria in the early 1900s and has gone on to become one of the most familiar, enduring species in the hobby. It has suffered as a result of its popularity to a certain extent with the mass-produced fish we see today lacking much of the colour seen in wild specimens and even exhibiting morphological deformities in some cases. Several selectively-bred ornamental strains have also...

Trigonostigma somphongsi
Cyprinidae · Meinken, 1958
T. somphongsi is exceptionally rare both in nature and the hobby and was considered potentially extinct for around a dozen years before a trio were imported to Germany as contaminants among a batch of Boraras urophthalmoides in 2006. Since then it has been successfully bred and distributed to various experts, mostly in Thailand and Germany, in the hope of establishing a sustainable captive population. The possibility of a...

Vaillantella maassiFork-tailed Loach
Vaillantellidae · Weber & de Beaufort, 1912
This species is traded under various names including 'chocolate scissor-tailed loach', chocolate long-finned loach', 'red line cobra loach', 'spiny eel loach' and 'dragon loach'. It's apparently difficult to find in its natural habitats and thus time-consuming to collect, meaning it's rarely traded in numbers, sought after by enthusiasts and tends to carry a relatively high price tag when available. The genus currently contains just three...

Xenentodon cancilaFreshwater Needlefish
Belonidae · Hamilton, 1822
X. cancila is often seen referred to as 'freshwater garfish', and although it does superficially resemble the true gars of the family Lepisosteidae, it's actually a member of the Belonidae, or needlefishes, the majority of which are marine or estuarine in existence. There are currently just two species in the genus although the probable existence of a third member has been noted by Roberts (1989) among oth...

Xenentodon canciloides
Belonidae · Bleeker, 1854
This species is a near-exclusive inhabitant of the upper water column and appreciates surface cover in the form of floating or overhanging vegetation. Other décor is relatively unimportant but can consist of a sandy substrate with leaf litter plus some large driftwood branches and twisted roots. Plants which can grow rooted in sand can al...

Yasuhikotakia eosSun Loach
Botiidae · Taki, 1972
Y. eos isn't as commonly-traded as it once was but is still available occasionally. It's difficult to confuse with any other member of the genus due to its colour pattern consisting of yellow to reddish brown base body colour (can appear greyish in some specimens, especially post-import or when introduced to a new aquarium) with a metallic green/blue golden sheen and large darkish marking on either side of the caudal peduncle. The fins can be yellowish to reddish, and the dorsal and c...

Yasuhikotakia leconteiSilver Loach
Botiidae · Fowler, 1937
This species is sometimes confused with Y. modesta though in reality the two are readily distinguishable from one another by body shape since Y. lecontei is a slimmer, more elongate fish. Further, in Y. lecontei the overall body colouration is usually brownish with a gold/green sheen and the dark markings...

Yasuhikotakia modestaRedtail Loach
Botiidae · Bleeker, 1864
This species is one of the more commonly-encountered botiids in the hobby and is also sold as 'blue', 'orange-finned', or 'red-finned' botia/loach. It's sometimes subject to artificial colouring with bright blue or purple dyes and we strongly recommend you do not purchase such fish (they're illegal in several countries).

Yasuhikotakia morletiSkunk Loach
Botiidae · Tirant, 1855
This species is common in the hobby and also sold as 'skunk botia' or 'Hora's loach', the latter in reference to Botia horae Smith, 1931, currently considered a synonym of Y. morleti. It's similar in appearance to the rarely-seen Y. longidorsalis but can be told apart by the fact it has a dark stripe running over the dorsal surface (this giving rise to the vernacular name 'skunk loach') which is lacking in its relative. The two can be further separated...

Allenbatrachus grunniensFreshwater Toadfish
Batrachoididae · Linnaeus, 1758
This species is relatively common in the aquarium hobby but contrary to popular belief is not venomous in any way. Its dorsal and opercular spines can pierce the skin, however, meaning extreme caution is necessary when netting it or performing aquarium maintenance. The genus Allenbatrachus was erected in 1997 to accom...

Anabas testudineusClimbing Perch
Anabantidae · Bloch, 1792
This species isn't especially popular in the aquarium trade but is undoubtedly interesting despite its lack of colour. In addition to its survival ability in the absence of water it's also capable of producing audible sounds though the purpose of these has not been fully-studied. Naturally-occurring xanthic and albino forms have also been recorded. There is considerable confusion as to the taxonomic status of the two species currently occupying this genus, with ichthyologists widely...

Bagarius suchusCrocodile Catfish
Sisoridae · Roberts, 1983
The genus Bagarius is distinguished from all other genera in the putative subfamily Sisoridae by having markedly heterodont teeth in the lower jaw. Teeth are present in two or three outer rows of relatively numerous, close-set conical teeth, and one or two inner rows of less numerous, widely separated, and much larger conical teeth (vs. dentition of the lower jaw consisting of only small conical teeth, or a roughened bony plate).

Bagarius yarrelliGoonch
Sisoridae · Sykes, 1839
This species is clearly unsuitable for the home aquarium given its eventual size and natural behaviour, and we know of only a handful of private aquarists with the facilities required to house it long-term. The grouping currently contains four species but is in urgent need of review with a number of additional taxa thought to exist and B. yarrelli possibly representing a synonym of B. bagarius.

Channa marulioidesEmperor Snakehead
Channidae · Bleeker, 1851
This species is often confused with the nominal congeners C. marulius (Hamilton, 1822) and C. melanoptera (Bleeker, 1855) with all three presenting taxonomic problems. For example, C. marulioides exhibits a number of variations in colour pattern depending on collection locality with the most common possessing a brownish base colour with a series of dark, chevron-like markings along each flank and some scales margined posteriorly in white.

Channa maruliusBullseye Snakehead
Channidae · Hamilton, 1822
This species is also referred to as 'giant', 'great', 'cobra', or 'Indian' snakehead. Although currently-considered to be distributed throughout much of southern Asia it is widely-accepted to represent a complex of related species in need of additional research. A number of geographical variants exhibiting diffe...

Channa micropeltesGiant Snakehead
Channidae · Cuvier, 1831
C. micropeltes is also referred to as 'Indonesian', 'red', or 'redline' snakehead, the latter names in reference to the appearance of juveniles which often appear in the ornamental trade despite its unsuitability for home aquaria. It is somewhat hyperbolised in the media as a fearsome, invasive "monster" fish with a reputation for killing more fish than it can eat, and even the occasional human, although in reality...

Chitala blanciRoyal Featherback
Notopteridae · d'Aubenton, 1965
This species is also referred to as 'royal knifefish' in the aquarium trade but arguably has no place in the ornamental hobby given its adult size and specialised requirements. It can be distinguished from congeners by presence of many small, dark spots on the anterior portion of the body which merge to form oblique, irregular stripes extending onto the anal and caudal fins posteriorly.

Chitala lopisGiant Featherback
Notopteridae · Bleeker, 1851
This species is not collected for the aquarium trade at time of writing. In contrast to other members of the genus older juvenile and adult individuals lack dark markings on the body while the jaw is more pronounced.

Chitala ornataClown Featherback
Notopteridae · Gray, 1831
This species is also referred to as 'clown knifefish' in the aquarium trade. It arguably has no place in the ornamental hobby given its adult size and specialised requirements but remains inexplicably popular and an albino form has even been line-bred for the purpose. It can be distinguished from all congeners by presence of one or more rows of large ocellated spots above the base of the anal-fin, but...

Crossocheilus burmanicus
Cyprinidae · Hora, 1936
We've been unable to obtain a diagnosis for this species to date but it can at least be distinguished from those congeners traded as 'Crossocheilus siamensis' (an invalid name synonymous with C. oblongus, which is itself of questionable identity), 'Siamese algae eater', or 'SAE' by the fact that the dark lateral stripe does not extend into the caudal-fin. Members of Crossocheilus are characterised by...

Crossocheilus cobitis
Cyprinidae · Bleeker, 1854
Given its wide natural range it seems logical that this species is or has been available in the aquarium trade, although its correct name may never have been applied. It is told apart from congeners by the following combination of characters: two pairs of barbels; a continuous midlateral stripe from the tip of the snout to the base of the caudal-fin, with a conspicuous small blotch at the posterior extremity, faintly marked on the caudal-fin; a faint mark between the anus and the anal-fin origin in juveniles; a narrow mouth.

Ctenopharyngodon idellaGrass Carp
Cyprinidae · Valenciennes, 1844
Despite being a wholly unsuitable aquarium subject, C. idella is often traded as such, with an albino form having been developed specifically for the ornamental market. Individuals which have outgrown their aquarium or pond should never be released into natural waters, either, since this species has proven capable of causing serious environmental damage under a wide range of climatic conditions.

Cyclocheilos enoplos
Cyprinidae · Bleeker, 1849
In the Mekong, it has been observed to migrate upstream from Phnom Penh to Khone Falls between November and February, returning downstream between May and August. The downstream migration ends in the Mekong delta area in Vietnam, where the fish remain until the floods reach their peak in October and November. These lower Mekong migrations mostly comprise juveniles and sub-adults, whereas above Khone Falls...

Datnioides pulcherSiamese Tiger Perch
Datnioididae · Kottelat, 1998
The massive decline in wild populations, hypothesised to be in excess of 90% since the mid-1980s, is thought to have been caused by a variety of factors, including habitat alteration due to construction of dams and other infrastructure, removal of riparian vegetation, and urban pollution, plus over fishing for both human consumption and the aquarium trade.

Garra fuliginosa
Cyprinidae · Fowler, 1934
Following Rainboth (1996) distinguishing characters for G. fuliginosa include: presence of rostral and maxillary barbels; a well-developed, trilobed rostrum; possession of 10 gill rakers on the lower portion of the first gill arch; no mid-lateral body stripe; 32-34 lateral line scales; body dark with random lighter scales in places. Kottelat (2001) states that the species can be told apart from other Garra occurring in Laos by a combination of: snout with a secondary rostrum, proboscis about twice as wide...

Hampala macrolepidotaHampala Barb
Cyprinidae · Kuhl & van Hasselt, 1823
This species is also known by the vernacular 'jungle perch' or 'sidebar barb' and should not be considered an aquarium subject in all but the most extreme circumstances since it can grow to over 2 feet in length, weigh in excess of 5 kg and is a powerful, pelagic predator. It's also a popular sport fish with a reputation for striking hard.

Hemibagrus spilopterus
Bagridae · Ng & Rainboth, 1999
This species is relatively common in the aquarium trade but has been widely misidentified as the congener H. nemurus which is native to Java and may never have been exported for ornamental purposes. Hemibagrus has been divided into a number of putative species groups which may or may not rep...

Hemibagrus wyckiiCrystal-eyed Catfish
Bagridae · Bleeker, 1858
Aggressively territorial and incompatible with other fishes in all but the largest public installations and even then may attack its tankmates. It's also one of few freshwater fishes that appear unafraid of humans meaning care must be exercised when performing maintenance.

Hemibagrus wyckioidesAsian Red Tailed Catfish
Bagridae · Fang & Chaux, 1949
Juvenile specimens are sometimes available in the aquarium trade although their purchase is strongly discouraged, and this species probably shouldn't be considered a home aquarium subject at all given its eventual size plus the fact it can live for several decades. H. wyckioides can be told apart from mos...

Hypsibarbus malcolmiGoldfin Tinfoil Barb
Cyprinidae · Smith, 1945
H. malcolmi is distinguished from congeners by the following combination of characters: 12-17 (usually 14-15) rakers on first gill arch; usually 16 circumpeduncular scale rows; less than 30 lateral line scales; some branched lateral line canals, but branching not extensive, median portion of dorsal-fin dark.

Incisilabeo behri
Cyprinidae · Fowler, 1937
The monotypic genus Incisilabeo is separated from the closely-related taxon Bangana by presence of a unique and conspicuous transverse notch across the top of the head, comparable in position to the ethmoid furrow in Bangana species. This notch approaches the eye, and the top of the head bulges forward, with the nostrils located partially beneath this projection and immediately anterior to the eyes. Tubercles cover the upper portion of the rostral fold, lower part of the notch, and upper surface of the forehead projection...

Labeo chrysophekadionBlack Shark
Cyprinidae · Bleeker, 1849
L. chrysophekadion is also known as 'black sharkminnow'. It continues to be available in the ornamental trade despite its patent unsuitability for the home aquarium, and an albino form has been selectively bred for the purpose. It can be distinguished from other members of the genus by the following combination...

Leptobarbus rubripinnaRed-finned Cigar Shark
Cyprinidae · Fowler, 1937
This species was referred to as its congener Leptobarbus hoevenii for a number of decades and continues to be misidentified as such in the aquarium hobby, with both species traded under the same name. It is a popular sport fish in its native countries and is wholly unsuitable for private aquaria. Unfortunately it is...

Macrochirichthys macrochirusGiant Sword Minnow
Cyprinidae · Valenciennes, 1844
It is thought to have been extirpated from the Chao Phraya and Mae Klong rivers, Lake Songkhla, and the entire island of Java due to a variety of anthropogenic factors, and the Mekong populations have also been drastically reduced. In particular, it is sensitive to pollution and gillnetting, and is heavily overfished.

Mekongina erythrospila
Cyprinidae · Fowler, 1937
Endemic to the middle and lower Mekong River system in Laos, Thailand, Cambodia, and Vietnam. Its known range extends from Chiang Rai province, Thailand in the north to Kratie province, Cambodia in the south, and it occurs in several important tributary systems including the Sesan, Srepok, and Tonlé Sap. Type locality is 'Mekong River at Kemarat, Thailand'.

Notopterus notopterusBronze Featherback
Notopteridae · Pallas, 1769
This species is also referred to as 'Asian knifefish' or 'ghost knifefish' in the aquarium trade in the aquarium trade but arguably has no place in the ornamental hobby given its adult size and specialised requirements. It is sometimes confused with the African species Xenomystus nigri but is easily told apart by its larger adult size and presence (vs. absence) of a dorsal fin.

Phalacronotus apogon
Siluridae · Bleeker, 1851
P. apogon has formerly been placed within the genera Kryptopterus, Micronema (Rainboth, 1996) and more recently Phalacronotus (Ferraris, 2007) and is an important food fish across much of its native range. It's very similar to P. micronema but can be told apart by its longer head (HL fits 4.6± 5.3 times in...

Scleropages formosusAsian Arowana
Osteoglossidae · Müller & Schlegel, 1840
This species is distinguished from its Australian congeners S. jardinii and S. leichardti by possessing a lower number of lateral line scales (21-26 vs 32-36). It occurs naturally in a number of colour forms of which three were elevated to distinct species status in 2003, but the current majority view is that all represent S. formosus pending a detailed review. Kottelat (2013) mentions that the red form may...

Amblyrhynchichthys micracanthus
Cyprinidae · Ng & Kottelat, 2004
Native to the Mekong River drainage in Laos (where Vientiane province represents the upper limit of its range), Thailand, Cambodia, and Vietnam, and the Tapi, Chao Phraya, and Mae Klong systems in Thailand. Type locality is '22 kilometers upstream from Phnom Penh, Tonle Sap River, Kandal Province, Cambodia'.

Bangana devdevi
Cyprinidae · Hora, 1936
Known with certainty from the Irrawaddy River system in Manipur state, India, and Myanmar, and the Salween watershed in eastern Myanmar and northwestern Thailand. Records from the Red River basin in Vietnam appear questionable. Type locality is 'Burma: Myitkyina District: Mali Hka basin: Phungin Hka;'.

Garra notata
Cyprinidae · Blyth, 1860
G. notata is one of a number of congeners to lack both a transverse groove and a proboscis on the snout. It also possesses 33-34 lateral line scales and a series of dark spots at the base of the dorsal-fin rays, and lacks scales on the lower portion of the body and abdomen. The genus Garra is a particularly enigmatic grouping with new taxa...

Garra salweenica
Cyprinidae · Hora & Mukerji, 1934
G. salweenica can be distinguished from other congeners inhabiting the Salween watershed by the following combinatuion of characters: body brownish; presence of a trilobed proboscis on the snout; snout blunt; a series of black spots at the base of the central dorsal-fin rays; presence of longitudinal stripes on the posterior portion of the body; a dark marking at the tip of the upper (and lower in some specimens) caudal-fin lobe; body depth 22.4-25.3 % SL.

Garra theunensis
Cyprinidae · Kottelat, 1998
This species can be distinguished from congeners in Southeast Asia and China by the following combination of characters: plain brown body and fins, sometimes with 6-8 narrow, faintly distinct, longitudinal stripes; snout triangular in dorsal view, with small tubercules and without transverse groove...

Gymnostomus lineatus
Cyprinidae · Smith, 1945
Recorded from the middle to lower Mekong river basin in southern China (Yiunnan province), Laos, Thailand, and Cambodia, plus the Chao Phraya watershed in central Thailand. Type locality is 'Thailand: Lam Ton Lang, a tributary of Menam Sak [Mae Nam Pa Sak; Ban Lam Thong Lang, village northwest of Pakjong'.

Gymnostomus lobatus
Cyprinidae · Smith, 1945
G. lobatus can be distinguished from congeners by the following combination of characters: possession of 32-33 + 2-3 lateral line scales; 5½ scale rows between lateral line and base of dorsal-fin; body relatively slender, depth fits 3.7-4.0 times in SL; snout often projecting strongly; body plain silver in colour.

Gymnostomus ornatapinnis
Cyprinidae · Roberts, 1997
G. ornatapinnis can be distinguished from congeners by the following combination of characters: head small; snout relatively short and blunt; caudal peduncle very deep; pectoral, pelvic, and anal fins usually reddish-orange or rose-tinted; pelvic and anal fins often with white tips; barbels completely absent.

Gymnostomus siamensisSiamese Mud Carp
Cyprinidae · Sauvage, 1881
G. siamensis can be distinguished from congeners by the following combination of characters: possession of 5½ lateral line scales; body relatively deep, depth fits 3.2-3.4 times in SL; head large and broad, width fits 5.5-6.7 times in SL; snout not or only weakly projecting; body plain silver in colour with no dark marking on caudal peduncle.

Hemibagrus filamentus
Bagridae · Fang & Chaux, 1949
This species appears to be unknown in the aquarium trade but is a valued food fish within its native range. Hemibagrus has been divided into a number of putative species groups which may or may not represent monophyletic assemblages, and following a major review by Ng and Kottelat (2013) H. filamentus is included in the H. nemurus group.

Hemibagrus microphthalmus
Bagridae · Day, 1877
This species cannot be considered a suitable home aquarium subject given its eventual size plus the fact it can live for several decades. It can be told apart from most oth...

Hypsibarbus pierreiYellow Eyed Silver Barb
Cyprinidae · Sauvage, 1880
Known from the middle and lower Mekong basins in Laos, Thailand, Cambodia, and Vietnam, plus the Dong Nai drainage in central Vietnam. Type locality is 'Rapids of Dang-nai, Bien Hoa Province, Thailand', which corresponds to what is now the city of Biên Hòa in Đồng Nai province, southern Vietnam.

Hypsibarbus salweenensis
Cyprinidae · Rainboth, 1996
Endemic to the Salween river system in Yunnan province, southern China, eastern Myanmar, and northwestern Thailand. Type locality is 'Salween River midway between Mae Sam Laep and Paleh, Mae Hong Son province, Thailand.'

Labeo pierrei
Cyprinidae · Sauvage, 1880
This species can be distinguished by the following characters: juveniles with brown body and dark marking at base of caudal-fin; 37-42 + 3-4 lateral line scales; 11½ branched dorsal-fin rays; 7½ scale rows between lateral line and dorsal-fin origin; 20-25 predorsal scales; dorsal-fin relatively small with anterior branched rays shorter than head in juveniles, slightly longer than head in adults.

Labiobarbus siamensis
Cyprinidae · Sauvage, 1881
L. siamensis can be distinguished from congeners by the following combination of characters: 39-42 scales in the lateral series; shoulder spot usually absent, but sometimes well-defined; body with longitudinal stripes formed by a spot on each scale; dorsal fin with dusky median stripe and no red coloration; caudal fin dusky, sometimes with reddish coloration, but no well-defined stripes; 20-23 circumpeduncular scales...

Mystacoleucus atridorsalis
Cyprinidae · Fowler, 1937
This species can be distinguished from congeners by the following combination of characters: body depth fits 2.5-2.7 times in SL; 28-31 +2-3 lateral line scales; 14-16 circumpeduncular scale rows; 5-5½ scale rows between the lateral line and dorsal-fin origin; a triangular distal blotch on the dorsal-fin; a few body scales with crescent-shaped black edges; a thin dark margin on the dorsal-fin, posterior to the distal blotch; a dark posterior margin on the caudal-fin; normally a single pair of rudimentary barbels present.

Mystacoleucus chilopterus
Cyprinidae · Fowler, 1935
Known from the middle Mekong basin in Laos and Thailand, including the Mun tributary drainage on the Khorat Plateau in northeastern Thailand, plus the Chao Phraya and Mae Klong watersheds in central and western Thailand, respectively. In the Mekong system it may also occur further upriver in Yunnan province, China, while the Khone Falls in Laos appear to represent its downstream limit.

Mystacoleucus ectypus
Cyprinidae · Kottelat, 2000
Known from the middle Mekong basin in Laos and Thailand, and may be endemic to the Khorat Plateau. Records exist from the Mun and Songkhram watersheds in northeastern Thailand, and a number of Mekong tributaries in laos, including the Nam Mang and Nam Kou drainages. Type locality is 'Nam Mang downstream of Ban Thabok, between 18°22'25"N, 103°13'30"E, and about 1 kilometer upstream, Vientiane Province, Laos'.

Mystacoleucus lepturus
Cyprinidae · Huang, 1979
This species can be distinguished from congeners by the following combination of characters: body relatively slender, depth fitting 3.4-3.8 times in SL; 32-33 + 2 lateral line scales; 14 circumpeduncular scale rows; presence of a single pair of barbels; black distal margin on dorsal-fin; numerous body scales with dark, crescent-shaped markings.

Nemacheilus troglocataractus
Nemacheilidae · Kottelat & Géry, 1989
Known only from a single cave system (Tham Sai Yok Noi) near the town of Nam Tok Sai Yok Noi, Sai Yok district, Kanchanaburi Province, Thailand. The headwater stream running through the cave is part of the Khwae Noi river basin, itself a tributary of the upper Mae Klong system. 621 metres of the cave system has repor...

Schistura deansmarti
Nemacheilidae · Vidthayanon & Kottelat, 2003
Type locality is 'Tham [=cave] Phra Sai Ngam, about 200 meters from entrance, Thung Salaeng Luang National Park, Phitsanulok Province, Thailand, 16°37'22"N, 100°39'47"E', and this species is endemic to the Tham Phra Sai Ngam cave system. Tham Phra Sai Ngam is a limestone cave system about 1.7 km long and containing a subterranean stre...

Schistura oedipus
Nemacheilidae · Kottelat, 1988
It's known from five caves in total, the others being Tham Huet, Tham Ban Louk Kow Larm, Tham Nong Pha Cham, and Tham Mae Lana. Streams flowing from these caves drain into the Nam Lang and Nam Khong rivers of the Salween drainage system, and the two easternmost caves, Tham Huet and Tham Nong Pha Cham, are both tributaries of the former.

Bagarius bagarius
Sisoridae · Hamilton, 1822
There is considerable confusion surrounding the identity of B. bagarius with its name having been widely applied to a relatively small species that is said to reach only 200 mm SL and considered to be common in northern India and much of Indochina.