Sumatra

The horseface loach, Acantopsis dialuzona, is a cobitid loach from Sumatra, Borneo, Java and Peninsular Malaysia, and possibly Thailand. Most literature lists it as A. choirorhynchos, which Kottelat treats as a junior synonym, and few if any fish in the trade come from near the type locality, so they may represent an unidentified species. Juveniles are exported in large numbers but adults are uncommon in the hobby, and it needs soft sand to bury in.

The Asian banjo catfish, Acrochordonichthys rugosus, is an akysid catfish from Java, Sumatra, Borneo, Peninsular Malaysia and southern Thailand. The most commonly encountered member of the genus in the trade, it is still by no means common, and body colouration varies widely even among fish from a single locality. Like its congeners it can secrete a milky substance from the axillary pore when stressed, and this can quickly kill other fishes in the confines of an aquarium.

The silver shark, Balantiocheilos melanopterus, is a large cyprinid from Borneo, Sumatra and possibly Peninsular Malaysia. Also sold as the 'Bala shark', it is among the most commonly encountered ornamental fishes, yet it reaches 300 to 350 mm SL and long-term care is beyond most hobbyists. Wild populations have dwindled or vanished, it has been listed as Endangered by the IUCN since 1996, and fish on sale are almost certainly all commercially bred. It does not occur in Indochina.

Balitoropsis zollingeri is a balitorid loach described from Java and recorded from Sumatra, Borneo, Peninsular Malaysia, Thailand, Laos and Cambodia. An obligate dweller of swiftly flowing streams and headwaters, it lives on riffles and runs over gravel, rocks and bedrock carpeted with biofilm. It needs clean, well-oxygenated water with strong turnover in the aquarium. It lives in aggregations in nature and is less bold when kept singly or in small numbers, so a group of six or more is best.

The spotted barb, Barbodes binotatus, is a cyprinid ranging from Myanmar and Thailand through the Greater Sunda Islands to the Philippines. So ubiquitous across its range that it's often called simply 'common barb', it occurs from sea level to at least 2000 m in habitats from fast-flowing hill streams to irrigation canals and floodplain ponds. The basic pattern of a dark spot at the dorsal-fin origin and another on the caudal peduncle varies with origin.

Barbodes everetti is a cyprinid from Borneo, known from Sarawak and West Kalimantan, where it lives in clear forest streams in the foothills. Uncommon in the hobby, its name has been widely misapplied to the clown barb, B. dunckeri, from Peninsular Malaysia and Singapore. B. everetti is the less colourful of the two, with relatively small dark body markings, a dark blotch at the rear of the dorsal-fin base and 3½ scales above the lateral line.

The spanner barb or 'T-barb', Barbodes lateristriga, is a cyprinid from peninsular Thailand, Peninsular Malaysia, Singapore, Sumatra and Java. Its colour pattern varies with locality, and the form most commonly seen in the trade corresponds most closely to fish from Johor. The species may prove to be a complex of closely-related taxa. Quite boisterous, it can intimidate more timid species with its size and activity, especially at feeding times.

Belodontichthys dinema is a large, open-water predatory catfish from the Malay Peninsula, Sumatra and Borneo that reaches 100 cm TL in the wild. It eats only fish and needs a very large aquarium without tankmates small enough to swallow. Fish exported from Thailand or elsewhere in Indochina under this name are likely to be B. truncatus, the species found in the Mekong and Chao Phraya basins.

The Java combtail, Belontia hasselti, is a labyrinth fish from peninsular Thailand, Peninsular Malaysia, Singapore, Sumatra, Borneo and Java. Also known as the 'Malay combtail', it mostly inhabits acidic forest peat swamps with little water movement. It differs from its only congener, B. signata, in its brownish grey body and the mosaic pattern in its unpaired fins. Growing to 200 mm SL, it will eat very small fishes and is not recommended for the average community aquarium.

The slender betta, Betta bellica, is a bubble-nesting labyrinth fish from Peninsular Malaysia and northeastern Sumatra, Indonesia. It lends its name to the B. bellica group of long, slender fishes with iridescent green markings on each scale. Most often found in peat swamp forests and blackwater streams, it feeds almost entirely on insects and is a prodigious jumper, seen leaping to take prey from overhanging leaves. Populations are often labelled by locality to preserve pure bloodlines.

The scarlet betta, Betta coccina, is a small bubble-nesting labyrinth fish from Jambi and Riau provinces in Sumatra and Johor in Peninsular Malaysia. It lends its name to the B. coccina group and is a stenotopic inhabitant of peat swamp forests and associated streams. Males carry an iridescent green lateral blotch that females lack, and populations are often labelled by locality, such as Jambi, Riau or Johor, to preserve pure bloodlines.

Betta cracens is a mouthbrooding labyrinth fish from the Jambi area of Sumatra, Indonesia, and it may also occur on nearby Bangka island. The most slender member of the B. pugnax complex, it is rare in the hobby, and most fish sold under the name are misidentified or mislabelled B. pugnax, B. raja or related species. Fish collected on Bangka have appeared in the hobby as Betta sp. 'Bangka'.

Betta dennisyongi is a small mouthbrooding labyrinth fish from the western coast of central Aceh province, northwestern Sumatra, Indonesia. It belongs to the B. rubra group and is typically exported mixed with the similar B. rubra, so the two may have been inadvertently hybridised before its description by Tan (2013). It has been collected among submerged leaf litter in lowland hill streams and acidic freshwater swamps.

Betta edithae is a paternal mouthbrooding labyrinth fish from Indonesia, recorded across Kalimantan, southern Sumatra, Bangka, Belitung and Bintan. The only member of the B. edithae group, it is separated from all other Betta spp. by its opaque or translucent branchiostegal membrane and posterior opercle. Fish from Bintan differ from Bornean specimens in several characters, and it remains unclear whether all populations are conspecific.

Betta falx is a small paternal mouthbrooding labyrinth fish endemic to Sumatra, Indonesia, where most collections come from Jambi province. A member of the B. picta group, it has greenish blue iridescent opercular scales and a reddish distal band on the anal and caudal fins. It inhabits shaded forest swamp streams and pools, some only a few centimetres deep, with negligible mineral content and a low pH.

Betta hipposideros is a paternal mouthbrooding labyrinth fish from peat swamps in western Peninsular Malaysia and eastern Sumatra, Indonesia. A member of the B. waseri group, it is most easily told from its relatives by a black horse-shoe shaped marking on the throat. An obligate inhabitant of peat swamps and blackwater streams, where the pH can be as low as 3.0 or 4.0, it may have to survive for several weeks in moist leaf litter at certain times of year.

The crescent betta, Betta imbellis, is a labyrinth fish thought to be native to southern Thailand, Peninsular Malaysia and northern Sumatra. It has been line-bred for aggression in southern Thailand and hybridised with B. splendens and other congeners for the ornamental trade, producing colour forms that do not occur naturally. Introduced ornamental forms and other Betta spp. are having an adverse effect on the genetic integrity of some wild populations.

Betta pardalotos is a large paternal mouthbrooding labyrinth fish from the Musi drainage near Palembang, South Sumatra, Indonesia. A member of the B. waseri group, it is best told from its relatives by the throat, which has two white, roundish patches on a black background. It is possibly endemic to the lower Musi basin, and the type series came from small freshwater channels draining into the river.

Betta raja is a mouthbrooding labyrinth fish endemic to Sumatra, Indonesia, found in the Batang Hari and Indragiri river basins. Before its description it was widely misidentified as Betta fusca. It lives in lowland forest swamps with both clear and black water, and mature males of this B. pugnax complex member have very long pelvic fins and black marginal bands on the anal and lower caudal fins. Populations from different localities should be labelled as such to preserve pure bloodlines.

Betta renata is a mouthbrooding labyrinth fish from forest peat swamps in Jambi, South Sumatra and Riau provinces on Sumatra, Indonesia. A member of the B. waseri group, it is most easily identified by a clearly-defined dark, kidney-shaped blotch on the throat that is always separate from the dark lower jaw. Its blackwater habitats can have a pH as low as 3.0 or 4.0, and at certain times of year the fish may be forced to survive in moist leaf litter for several weeks.

Betta rubra is a small labyrinth fish from northwestern Sumatra, Indonesia, known from the Singkil area of Aceh and around Sibolga in North Sumatra. Conflict in the region meant it was known only from the type specimens for around 100 years, and it began to appear in the hobby in early 2007. It is typically exported mixed with the similar-looking B. dennisyongi and may have been hybridised with it. The two are told apart mainly by the opercle pattern and the width of the triangular black mark below the eye.

Betta simorum is a slender bubble-nesting labyrinth fish from Sumatra and the Kapuas River system in West Kalimantan, Borneo, Indonesia. Growing to around 90 mm SL, it inhabits heavily-vegetated forest peat swamps and blackwater streams. It shares the B. bellica group with B. bellica, from which it differs in its slanted head with a concave profile behind the eye. Populations are often labelled by locality, such as Rantau Panjang or Sungai Bengkwan, to preserve pure bloodlines.

The dwarf rasbora, Boraras maculatus, is a miniature cyprinid from Peninsular Malaysia, southern Thailand, eastern Sumatra, Singapore and Bintan. It inhabits blackwater streams and rivers associated with forest peat swamps, where the water is very soft and acidic. Colour pattern varies between populations, some forms showing more intense red than others. It is most similar to B. naevus, in which the red body colouration does not extend into the head.

Brevibora cheeya is a small cyprinid from Peninsular Malaysia, Sumatra and the island of Bangka. The type locality is a slow-flowing, acidic stream in coastal heath forest over sand and peat. Very rare in the trade, it is normally imported only as bycatch among other fishes. A complete lateral line, more scales in the lateral row and a larger adult size separate it from the better-known B. dorsiocellata.

The eyespot rasbora, Brevibora dorsiocellata, is a small cyprinid from southern Thailand, Peninsular Malaysia, Borneo and Sumatra. It is also traded as the 'green-eyed', 'emerald-eyed' or 'hi-spot' rasbora. The common, commercially produced form is plain-coloured with a greenish-blue reflective patch in the eye, while a probably wild-caught form seen from time to time has russet red at the base of the tail. Some Bornean records may refer to B. cheeya.

The red-tailed redeye puffer, Carinotetraodon irrubesco, is a small freshwater puffer endemic to Indonesia, known from Sumatra and West Kalimantan. Males have a reddish caudal fin and lack the black spot at the dorsal-fin base seen in the other red-eyed puffers, and the eyes bulge clearly above the head. It has been collected only among submerged riparian vegetation of terrestrial origin, in murky brown water.

The dwarf snakehead, Channa gachua, is a snakehead recorded across an enormous range from Iran to Taiwan and Bali. There is significant evidence that C. gachua as currently understood is a complex of similar-looking species in need of taxonomic review. A mouthbrooder bred regularly in captivity, it can share a well-chosen community with peaceful fishes too large to be prey, but populations should not be mixed as some may hybridise.

The forest snakehead, Channa lucius, is a predatory snakehead from Indochina, Peninsular Malaysia and the Greater Sunda Islands. Also referred to as the 'splendid' or 'shiny' snakehead, it occurs on Sumatra, Borneo and Java, grows to 400 mm SL and favours forest swamps and tributaries. Like others in the genus it breathes atmospheric air, and it needs a dimly-lit tank with plenty of cover and a tightly-fitting lid, since Channa spp. are notorious for their ability to escape.

The black snakehead, Channa melasoma, is a snakehead from southern Thailand, Peninsular Malaysia, Singapore, Borneo, Sumatra and the Philippines. It can be told apart from the similar C. baramensis, once considered a synonym, by lacking a black spot in the centre of many body scales and a barred caudal fin. In nature it appears to favour clear forest streams with mud and leaf litter, but it has also been recorded from acidic blackwater in peat swamp forest.

The ocellated snakehead, Channa pleurophthalma, is a snakehead native to southeastern Sumatra and the Kapuas and Barito basins of Indonesian Borneo. It lives in streams and mangroves and is among the few snakeheads known to form aggregations throughout its life. Unlike most Channa spp. it is pelagic and needs plenty of swimming room, with a tank of at least 240 x 60 cm recommended for a fish reaching 350 mm SL.

The clown loach, Chromobotia macracanthus, is a large botiid loach native to river systems of Borneo and Sumatra in Indonesia. Widely sold, it is wholly unsuitable for smaller aquaria: a group needs a tank of at least 180 x 60 cm, and a properly kept fish can live for more than twenty years. Bornean and Sumatran populations differ slightly in pattern, and in the Batang Hari, Sumatra, drifting larvae are now collected and grown on for the trade.

Crossocheilus langei is a cyprinid from Borneo, Peninsular Malaysia and Thailand, one of several near-identical fish sold as the Siamese algae eater. The trade name 'Crossocheilus siamensis' used for these fish is not valid. C. langei can be told apart by a dark blotch in front of the anal fin and a lateral line running straight through the dark body stripe.

The beardless barb, Cyclocheilichthys apogon, is a cyprinid ranging from Myanmar to Vietnam and south via Peninsular Malaysia to Borneo and Sumatra. Also sold as 'skinhead barb', it lacks barbels and has a black blotch at the caudal-fin base plus rows of dark spots along the scale rows. It favours slower-moving or still water and grazes the biofilm on submerged roots and branches. Rarely imported in numbers, it most often arrives as bycatch.

Cyclocheilichthys armatus is a cyprinid ranging from the Mekong region through Thailand and Peninsular Malaysia to Borneo, Sumatra and Java. It forages from mid-water to the bottom of rivers in the dry season and is thought to migrate into flooded forest to breed. Rarely imported in numbers and most often arriving as bycatch, it makes a peaceful, unusual addition to larger aquaria in a group of at least six.

Cyclocheilichthys heteronema is a cyprinid ranging from Myanmar east to Vietnam and south to Peninsular Malaysia, Borneo and Sumatra. Its fimbriated barbels, extended downwards while it browses, are unique in the genus. It doesn't appear to be common in nature, with most records from Peninsular Malaysia, and it reaches the trade only as occasional bycatch. Very peaceful but retiring, it is easily outcompeted by boisterous tankmates.

Cyclocheilichthys repasson is a cyprinid with an enormous range, from the Mekong region and Myanmar through Peninsular Malaysia to Borneo and Sumatra. It grows to around 280 mm SL and favours slower-moving or still water, grazing the biofilm on submerged roots and branches. It is not often seen in the hobby. Most populations have a dark caudal peduncle spot, stripes formed by dark markings on the scales, and two pairs of barbels.

The pearl danio, Danio albolineatus, is a small cyprinid recorded from Myanmar and Indochina south to Peninsular Malaysia and Sumatra. Colour and patterning differ between localities, and doubts remain whether it is a single species or a group of closely related fish. Wild examples are rare in the trade, with most produced commercially in South East Asia or eastern Europe, and some of the fish traded are likely to be hybrids with D. roseus.

The silver tiger perch, Datnioides polota, is a tiger perch widely distributed in southeastern Asia, from India and Bangladesh east to Indonesia. Mostly found in brackish habitats such as estuaries, mangroves and coastal lagoons, it has a highly variable colour pattern with up to 7 dark bars. The name D. quadrifasciatus is sometimes applied to it, but that name is a junior homonym and polota takes precedence.

Desmopuntius gemellus is a rarely-traded cyprinid from eastern Sumatra and the island of Bangka, Indonesia. Like D. johorensis and D. trifasciatus, it is vertically barred as a juvenile and changes to a pattern of thin lateral stripes, a change that begins at around 20 mm SL and is normally complete by 30 to 40 mm. It inhabits peat swamp forests and associated black water streams.

Normally traded as the 'pentazona' barb, Desmopuntius hexazona is a cyprinid from southern Borneo, eastern Sumatra, Singapore and the Malay Peninsula. It is almost identical to D. pentazona, which has a small dark marking at the rear of the dorsal-fin base that D. hexazona lacks. Older literature may label it 'Puntius johorensis'. In Singapore it is considered highly endangered and is restricted to the Central Catchment nature reserve.

The striped barb, Desmopuntius johorensis, is a cyprinid from southern Thailand, Peninsular Malaysia, Singapore, Sumatra and Borneo. Juveniles have 4 dark vertical bars and develop 5 or 6 broad lateral stripes as they grow, a pattern change shared with D. gemellus and D. trifasciatus. Before Kottelat (1992) it was referred to as Puntius eugrammus, while the name 'Puntius johorensis' was misapplied to D. hexazona. It lives mainly in peat swamps and black water streams.

The flying fox, Epalzeorhynchos kalopterum, is a cyprinid from southern Thailand, Peninsular Malaysia and the Greater Sunda Islands. Fishes sold as 'false flying fox' or 'Siamese flying fox', such as Garra cambodgiensis and Gyrinocheilus aymonieri, are often confused with it, but it has white-edged red and black fins and two pairs of barbels. It grows increasingly territorial with age and can live for over 15 years.

The 'freshwater' moray eel, Gymnothorax tile, is a moray from coastal regions of the Indo-West Pacific, from eastern India to the Philippines. Although typically sold as a freshwater fish, this is not strictly the case, and the profile treats a marine salt mix as mandatory. It has small pale spots on a darker head and body, where the congener G. polyuranodon has much larger dark spots on a paler background. Highly piscivorous, it is best kept alone in all but the very largest aquaria.

The kissing gourami, Helostoma temminkii, is an anabantoid from southern Indochina and the Malay Archipelago, and the sole member of its family. The widely traded pinkish-white form is a leucistic variant bred for ornamental purposes, and the 'balloon' variety is intentionally disfigured and much shorter-lived. Its often belligerent behaviour, adult size and life span of over 20 years make it unsuitable for most home aquaria. The 'kissing' appears at least in part related to establishing social dominance.

Homalopterula gymnogaster is a hillstream loach from Sumatra, Indonesia, described from Lake Maninjau and recorded from Jambi province northwards. Tan and Kottelat (2009) describe it as a relatively common highland species of riffles and 'quiet waters'. That makes it unusual, since Homaloptera species are not normally associated with standing water, though it remains unclear whether the fish come from the lakes themselves or their outflowing rivers.

Homalopterula ripleyi is a hillstream loach known only from a small area of northern Sumatra, Indonesia, on the eastern slopes of the Barisan range. Fowler (1940) described it from a single specimen as the only member of his new genus Homalopterula. Gerhard Ott and Dirk Dettmers collected it in 2003 for the first time in over 60 years, from small, clear forest streams over bedrock, boulders, rocks and gravel.

Kottelatia brittani is a small rasborin cyprinid described from southern Peninsular Malaysia and recorded from the Batang Hari river in Sumatra. Its distribution is unclear, since the type specimens came via a Singapore wholesaler, and there appears to be a possibility that it is endemic to Sumatra. Sold as the 'head and tail light rasbora', it has been confused with Rasbora kalbarensis but is larger, with a more pointed head and intense orange to red blotches on the caudal peduncle.

Kottelatlimia pristes is a small cobitid loach from Peninsular Malaysia, Sumatra and Borneo, the most widely-distributed member of its genus. It inhabits small, slow-moving forest streams and peat swamps with tannin-stained water, often in piles of leaf litter. It turns up occasionally in the trade, sometimes as bycatch among other species and under names such as 'Sumatran mini royal loach' or Cobitis cf. sumatranus.

Kryptopterus bicirrhis is a silurid catfish from much of Southeast Asia, including the Mekong and Chao Phraya and the Greater Sunda Islands. Uncommon in the aquarium trade, its name was widely misapplied to K. vitreolus in older literature, but the two are easily told apart because K. bicirrhis does not have a transparent body in life. It tends to form schools, so four or more should be kept.

The blue sheatfish, Kryptopterus cryptopterus, is a silurid catfish from the Malay Peninsula, Singapore, Sumatra, Borneo and Java. It inhabits flowing rivers and larger streams with turbid water, and is sometimes traded as 'smokey glass catfish'. Populations from Thailand, Cambodia, Laos and Vietnam once considered conspecific are now referred to K. geminus, its closest relative, from which it differs in having a wider head and a shorter snout and anal fin.

Kryptopterus limpok is a silurid catfish widely distributed through Southeast Asia, including the Mekong and the Greater Sunda Islands. It can be told from its congeners by an extremely long mental barbel extending beyond the tip of the pectoral fin. It inhabits flowing rivers and larger streams with turbid water, grows to 260 mm and is almost unheard of in the ornamental trade.

The striped glass catfish, Kryptopterus macrocephalus, is a silurid catfish from Thailand, Malaysia, Singapore and the Greater Sunda Islands. A stenotypic inhabitant of peat swamp forests and associated blackwater streams, it is also known as the false, mottled or tawny glass catfish. Striped and mottled colour forms exist that may or may not be conspecific, and the similar K. piperatus has a pale brown body with scattered dark spots.

Kryptopterus palembangensis is a silurid catfish known only from central and southern Sumatra, in the provinces of Jambi and South Sumatra. It is closely related to K. bicirrhis but is told apart by a prominent, dark lateral stripe on each flank. Almost unheard of in the aquarium trade, it may occasionally be exported among shipments of wild fishes from Sumatra.

Labiobarbus leptocheilus is a large cyprinid widespread in Southeast Asia, from the Mekong and Salween to the Greater Sunda Islands. Different populations vary somewhat in appearance, and it may turn out to represent a group of closely-related species. The Cambodian Mekong population has been considered a distinct species, Labiobarbus lineatus, and that name is widely used in the ornamental trade although it is currently a synonym. It grows to 260 mm SL and needs spotless, well-oxygenated water.

Labiobarbus ocellatus is a cyprinid from Peninsular Malaysia, Sumatra and Borneo, with a black spot on the shoulder and one on the caudal peduncle. It is occasionally available in the ornamental trade, typically under a name such as 'Bornean eye-spot silver shark' or the invalid scientific name Cirrhinus chinensis. A pelagic species of rivers and some lakes, it moves into seasonally inundated floodplains and forest during the wet season, and grows to 180 mm SL.

Lepidocephalichthys furcatus is a small cobitid loach from Peninsular Malaysia, southern Thailand and North Sumatra, Indonesia. Not traded often, it turns up occasionally as bycatch among shipments of other species. It is told apart from congeners most easily by the prominent, roughly semi-circular lamina circularis in males, a feature unique within the genus, and it has a forked caudal fin.

Lepidocephalichthys hasselti is a cobitid loach described from Java and recorded from Myanmar to Vietnam, Peninsular Malaysia, Sumatra and Borneo. Its wide distribution makes it relatively common in the aquarium hobby. Colour and pattern vary with locality and have led to problems with identification, and the flanks usually show a row of dark blotches or a solid stripe with a light, unpigmented stripe above.

Lepidocephalichthys tomaculum is a small cobitid loach from Peninsular Malaysia, with a single tentative record from Lampung Province, Sumatra. It inhabits shallow, slow-moving streams, swamps, oxbows and backwaters over mud, silt or peat. Occasionally available as bycatch, it has a reddish brown body with thin dark bars across the back, and where it lives with L. hasselti identification can be difficult.

Lepidocephalus macrochir is a cobitid loach described from Sumatra and since recorded from Thailand, Peninsular Malaysia, Java and Borneo. It is traded sporadically as the 'pinky loach', 'deep water kuhli loach' and 'Borneo high body cave loach'. Although sometimes said to be a cave loach, Thai collectors report it from deep water, and in aquaria it spends a lot of time buried in soft substrates.

The apollo shark, Luciosoma setigerum, is a slender cyprinid found across much of Southeast Asia, from the Mekong basin to Borneo, Sumatra and Java. Subadults are traded regularly and are frequently confused with L. bleekeri, which lacks the series of black spots on the lateral line scales. A similar fish of unknown origin with no stripe on the front of the body is also common in the trade, listed as L. cf. setigerum. It needs the largest private aquaria.

Mystacoleucus obtusirostris is a riverine cyprinid found from Myanmar and southwestern China to Vietnam, Borneo, Sumatra and Java. Referred to as M. marginatus for decades, it is the most widely distributed member of the genus, and populations vary somewhat in colour pattern. It is occasionally marketed as 'Burmese rainbow barb'. A group of six or more is the smallest to consider, and like all Mystacoleucus it has a forward-pointing predorsal spine that can snag in a net.

Nemacheilus selangoricus is a nemacheilid loach ranging from southern Thailand through Peninsular Malaysia and Singapore to western Borneo and Sumatra. It is most common in shallow, flowing forest streams over sand, gravel and detritus. It belongs to the N. selangoricus group and is most similar to N. spiniferus, from which it differs in its 8-12 very regular dark bars on the flanks.

The checkered barb, Oliotius oligolepis, is a small cyprinid apparently endemic to western central Sumatra, Indonesia. Also traded as 'checker barb', 'checkerboard barb' or 'island barb', it is farmed commercially in enormous numbers and wild examples are rarely, if ever, available. Kottelat (2013) raised the genus Oliotius for it, diagnosed partly by black crescent-shaped marks on all scales.

The Javanese ricefish, Oryzias javanicus, ranges through Peninsular Thailand, Malaysia, Singapore and Indonesia as far east as Lombok and Sulawesi. Typically found in coastal, normally brackish, streams, pools and mangrove swamps, it tolerates a wide salinity range and has also been recorded in fresh water. It is exported on occasion and sometimes referred to as the 'blue-eyed ricefish'.

Traded as 'eel loach', Pangio anguillaris is a cobitid loach from Borneo, Sumatra, Peninsular Malaysia and the Chao Phraya and Mekong basins. It has an extremely elongated, worm-like body with 69-71 vertebrae and no nasal barbels, and is most commonly available as bycatch among shipments of other fishes. The species as currently recognised appears to represent a complex of closely-related taxa.

Pangio cuneovirgata is a small kuhli loach from southern Thailand, Peninsular Malaysia, Sumatra and western Java, found in forest streams and swamps. It has 7-13 dark saddles on the upper half of the body and looks most like P. malayana, but has nasal barbels and a truncate caudal-fin. It is infrequently encountered in the trade, most often as bycatch among shipments of similar-looking congeners.

Pangio malayana is a barred kuhli loach from Peninsular Malaysia, the Batang Hari drainage in Sumatra and the Kapuas system in Indonesian Borneo. It has 10-16 dark saddles on the upper half of the body and a black bar at the base of the caudal-fin, and looks most similar to P. cuneovirgata, which has a truncate caudal-fin. It is most often encountered as bycatch among shipments of similar-looking congeners.

The black kuhli loach, Pangio oblonga, is a plain-bodied cobitid from Java, Sumatra, Borneo, Peninsular Malaysia and Thailand. Among the more readily available Pangio in the hobby, it is also traded as 'Java loach', 'cinnamon loach' and 'chocolate kuhli loach'. The species will probably turn out to be a complex of closely-related taxa, with at least four genetic lineages identified.

Pangio piperata is a slender kuhli loach from Peninsular Malaysia, Riau Province in Sumatra and the Rajang river drainage in Sarawak. Its yellowish-brown body is peppered with small dark spots forming a rough stripe along the lateral line. Some populations of the variable P. shelfordii look similar and the two often occur together, but P. piperata is generally plainer and has fewer vertebrae. It is exported occasionally, most often as bycatch among congeners.

Usually sold as the 'kuhli' loach, Pangio semicincta is a cobitid loach from Peninsular Malaysia, Sumatra and Borneo. It lives in shallow forest streams and swamps, often in black water, and is typically abundant in leaf litter. P. kuhlii itself is currently considered endemic to Java and has possibly never been seen in aquaria, so the common aquarium 'kuhli' is more likely to be this species or an unidentified relative.

Pangio shelfordii is a variably patterned kuhli loach from Peninsular Malaysia, Singapore, Sumatra and Borneo. Its patterning varies within and between populations, and as currently understood the species represents an assemblage containing a number of unidentified taxa. Some Sumatran and Bornean populations resemble P. piperata, which often occurs alongside it. It is exported occasionally, often as bycatch among shipments of congeners.

Parosphromenus sp. 'Sentang' is a liquorice gourami said to come from Jambi province, central Sumatra, Indonesia, presumably the Sentang river. It is sometimes referred to by the invented name P. 'sintangensis'. It closely resembles P. bintan and P. sp. 'blue line', though the inner bluish bands in its dorsal, anal and caudal fins are perhaps a little narrower. Its habitat is unconfirmed.

The tiger barb, Puntigrus tetrazona, is a small cyprinid probably endemic to central and southern Sumatra, Indonesia. Among the most ubiquitous species in the aquarium trade, it is seen mostly as commercially-produced fish and ornamental strains, and wild examples are rarely traded. The identity of the 'aquarium' tiger barb is the subject of ongoing confusion, and many farmed fish are weak or deformed through inbreeding.

The lined barb, 'Puntius' lineatus, is a laterally-striped cyprinid from Peninsular Malaysia, Sumatra and Borneo, found mostly in peat swamps. It is most often confused with 'P.' johorensis, the two being the most common of the striped species in the trade, but it has no more than one pair of barbels, lacks vertical bars as a juvenile and grows smaller. Its habitats include black water streams stained brown with humic acids, with pH as low as 3.0 or 4.0.

The silver rasbora, Rasbora argyrotaenia, is a cyprinid from Peninsular Malaysia, Singapore, Sumatra, Java, Borneo and the Palawan islands. One of the larger rasboras at up to 140 mm TL, it is a plain, silvery fish with a faint dark stripe, and fish pictured under this name with a bold black stripe are probably a regional variant of R. daniconius. A DNA barcode study found two mitochondrial lineages under the name, and the species as currently recognised is likely to be split.

Rasbora dusonensis is a cyprinid from Sumatra, Peninsular Malaysia and Borneo, found in larger river channels and peat swamp blackwaters. Its identity was unclear for decades before its redescription by Ng and Kottelat (2013). It is very similar to R. tornieri, which shares the Musi river with it, but has a bright yellow caudal fin with a broad dark margin, against carmine red in R. tornieri. One specimen measured 162 mm SL, although 95 to 105 mm is a more commonly reported adult size.

Rasbora tornieri is a cyprinid from Sumatra, Borneo, Peninsular Malaysia and the Mekong drainage in Cambodia. Its identity was unclear for decades before its redescription by Ng and Kottelat (2013). It is very similar to R. dusonensis, which shares the Musi river with it, but its caudal fin is carmine red, against bright yellow in R. dusonensis. It lives in flowing streams and peat swamp blackwaters alike.

The chocolate gourami, Sphaerichthys osphromenoides, is a small gourami from Peninsular Malaysia, Sumatra and Borneo. By far the best known member of the genus, it mostly inhabits peat swamps and black water streams where the pH can drop to 3.0 or 4.0. A maternal mouthbrooder, it is slow-moving and easily outcompeted for food by more boisterous tankmates.

The orange-fin stiphodon, Stiphodon maculidorsalis, is a stream-dwelling goby known only from western Sumatra, Indonesia. Formerly referred to as S. sp. 'orange fin' or 'ST01', it is one of the more commonly traded members of the genus, often in single-sex batches, mixed with other species or misidentified as S. zebrinus. Small black spots on the top of the head and trunk, present in both sexes, are unique within the genus.

The rainbow stiphodon, Stiphodon ornatus, is a stream-dwelling goby known only from Aceh and West Sumatra provinces, Sumatra, Indonesia. Traded as S. sp. 'rainbow', 'gold fin' or 'gold cheek', it is among the more widely available members of the genus. More than one species may be sold under these names, and males vary a great deal in colour with mood, so identification can be tricky. All Stiphodon in the trade are wild-collected.

The cobalt blue goby, Stiphodon semoni, is a stream-dwelling goby ranging from western Sumatra east to northern New Guinea and the Solomon Islands. It has been traded for a number of years but often under the wrong name, including S. elegans and S. atropurpureus. Males have a bright blue metallic stripe from snout to caudal peduncle and rounded, almost hyaline dorsal fins, while those of S. atropurpureus are dusky to black.

Systomus orphoides is a large cyprinid ranging from Myanmar to Vietnam and south through Peninsular Malaysia to Borneo, Sumatra and Java. It mostly inhabits flowing tributaries and large streams, moving onto inundated farmland and forest in the wet season to feed and spawn. Not often available in the trade and usually seen as bycatch, it grows to 250 mm SL, is quite boisterous, and needs more-or-less spotless water.

Trigonopoma gracile is a small rasbora from the blackwater peat swamps of Peninsular Malaysia, Borneo and Sumatra. Its colour forms vary with collection locality. The name Rasbora agilis has been applied to it since a 1971 book pictured it under that name, but R. agilis is a junior synonym of T. pauciperforatum, the fish it is said to resemble.

The glowlight rasbora, Trigonopoma pauciperforatum, is a small cyprinid from Peninsular Malaysia, Singapore, Borneo and Sumatra. Also sold as the 'redline' rasbora, its lateral stripe varies from deep orange to golden with locality, diet, condition and mood. It inhabits blackwater streams associated with peat swamps, where the pH can drop as low as 3.0 or 4.0, and the name R. agilis is a junior synonym of it.

Trigonostigma hengeli is a small rasbora from the Greater Sunda Islands, collected in Jambi province, Sumatra and apparently West Kalimantan, Borneo. It is sometimes sold as the 'glowlight rasbora', a name also applied to Trigonopoma pauciperforatum. Slightly smaller than T. espei and T. heteromorpha, it has a greyish body with bright orange along the upper and anterior edges of the 'lambchop' marking.

The harlequin, Trigonostigma heteromorpha, is a small cyprinid from southern Thailand, Peninsular Malaysia, Singapore and Sumatra. First exported for aquaria in the early 1900s, it is now mass-produced, and farmed fish lack much of the colour of wild ones. The dark triangular body marking sets it apart from T. espei and T. hengeli, and two divergent lineages found in aquarium stock suggest the species as currently recognised may contain more than one taxon.

The fork-tailed loach, Vaillantella maassi, is a loach from Sumatra, Borneo, Peninsular Malaysia and southern Thailand. Traded as 'chocolate scissor-tailed loach' and 'dragon loach' among other names, it has a bluish-brown body with an orange to yellow dorsal stripe. Rarely traded in numbers, it is among the more reclusive loaches and can be aggressive with its own kind and other fishes.

Xenentodon canciloides is a freshwater needlefish from Borneo, Sumatra, Peninsular Malaysia and Thailand, and is considered to occur in the Mekong. Rarely seen in the ornamental trade, it is far less common there than its congener X. cancila, from which it differs in its slender, delicate jaws and smaller size, not exceeding 30 cm TL. A near-exclusive inhabitant of the upper water column, it is surprisingly peaceful with anything too large to swallow and is best kept in numbers of four or more.

The goonch, Bagarius yarrelli, is a very large sisorid catfish recorded from the Indus in Pakistan east through Indochina to Sumatra and Borneo. Also known as the 'giant devil catfish' and 'sand shark', it reaches 1300 to 2000 mm and is fished for food across much of its range. That wide distribution appears doubtful, and Indian and Southeast Asian populations may prove not to be conspecific. It lives among boulders in the fast, turbulent rapids of large rivers.

The emperor snakehead, Channa marulioides, is a large snakehead from southern Thailand, Malaysia and Indonesia, including Borneo and Sumatra. Colour pattern varies with locality, and it is often confused with C. marulius and C. melanoptera, all three presenting taxonomic problems. Growing to 650 mm SL, it is pelagic, turns aggressive towards its own kind at sexual maturity and is suitable only for public installations or the very largest private aquaria.

The giant snakehead, Channa micropeltes, is a predatory fish from Southeast Asia that grows to well over a metre. Juveniles are sold as 'red' or 'redline' snakehead, but it is suitable only for public installations or the very largest private aquaria. Unlike most Channa species it is pelagic and needs plenty of room to swim, and adults become aggressive at sexual maturity.

The giant featherback, Chitala lopis, is a notopterid accepted to range from the Mekong basin to Peninsular Malaysia, Sumatra, Borneo and Java. That range appears to require confirmation: it may already be extinct on Java, and the species may comprise several closely-related taxa. Older juveniles and adults lack the dark body markings of other Chitala and have a more pronounced jaw, and at up to 1500 mm SL it is suitable only for public installations or the very largest private aquaria.

Cyclocheilos enoplos is a large cyprinid from the Mekong region and Thailand south through Peninsular Malaysia to Borneo, Sumatra and Java. Growing to around 750 mm SL, it is clearly unsuitable for aquaria and scarce to non-existent in the ornamental trade. In the Mekong it makes long seasonal migrations, and adults move upstream above Khone Falls in what appear to be spawning migrations.

The Indonesian tiger perch, Datnioides microlepis, is a large tiger perch from Peninsular Malaysia, Sumatra and Indonesian Borneo. It has 6 to 7 wide dark bars and small body scales, lives only in large, deep lowland rivers, and grows to 500 mm SL. Juveniles may form groups, but adults are not gregarious and respond aggressively to conspecifics and similarly-shaped fishes.

The hampala barb, Hampala macrolepidota, is a cyprinid ranging from Myanmar through Thailand to the Mekong, and south to Borneo, Sumatra and Java. Also known as 'jungle perch' or 'sidebar barb', it can grow to over 2 feet and 5 kg and is a powerful, pelagic predator and not an aquarium subject in all but the most extreme circumstances. Prized as a food and sport fish, it has been introduced to numerous water bodies.

The crystal-eyed catfish, Hemibagrus wyckii, is a bagrid with an enormous distribution across central Indochina and western Indonesia. Juveniles are sometimes available in the aquarium trade, but buying them is strongly discouraged: it reaches 710 mm SL, is aggressively territorial and can live for several decades. Despite the common name, the blue eye is not given as a distinguishing character in any diagnosis we've seen.

The black shark, Labeo chrysophekadion, is a large cyprinid from Southeast Asia, including the Mekong, Chao Phraya and the Greater Sunda Islands. Also known as the black sharkminnow, it reaches 600 mm and is aggressively territorial towards conspecifics and similarly-shaped fishes. It continues to be sold despite its patent unsuitability for the home aquarium, and an albino form has been selectively bred for the trade.

The mad barb, Leptobarbus hoevenii, is a large pelagic cyprinid apparently native to Peninsular Malaysia, Borneo, Sumatra and Java. A popular sport fish growing to 800 to 1000 mm, it is wholly unsuitable for private aquaria but is readily available at 100 to 150 mm. The congener L. rubripinna was referred to as L. hoevenii for decades and both are traded under the same name. L. hoevenii lacks the broad dark midlateral stripe and has dark grey pelvic and anal fins.

The giant sword minnow, Macrochirichthys macrochirus, is a large pelagic cyprinid widespread in Southeast Asia, from the Mekong to Borneo and Sumatra. Growing to 600 to 800 mm and becoming increasingly piscivorous as it grows, it is unsuitable for the majority of private aquaria, although juveniles are traded on occasion. It is thought to have been extirpated from the Chao Phraya, Mae Klong, Lake Songkhla and Java, and the Mekong populations have been drastically reduced.

The bronze featherback, Notopterus notopterus, is an air-breathing notopterid from the Indian subcontinent and Southeast Asia. Also called 'Asian knifefish' or 'ghost knifefish' in the trade, it grows to 600 mm and arguably has no place in the ornamental hobby given its adult size and specialised requirements. The single species in Notopterus is likely to represent a complex of closely-related species.

Phalacronotus apogon is a large silurid catfish from much of Southeast Asia, including Thailand, the Mekong basin and the Greater Sunda Islands. It reaches 700 mm and arguably should not be considered a home aquarium subject at all, but juveniles are sometimes sold as 'blue neon sheatfish' or 'metallic cheatfish' without adequate information on long-term care. It is an important food fish across much of its native range.

The Asian arowana, Scleropages formosus, is an osteoglossid from the Mekong system, eastern Thailand, Peninsular Malaysia, Sumatra and Borneo. Highly valued in the aquarium trade since the 1970s and listed on Appendix I of CITES since 1975, it is now extirpated across much of its range. It occurs in several colour forms, such as the 'super red' of the upper Kapuas, and three were described as species in 2003, though the majority view treats all of them as S. formosus pending review.

Labiobarbus fasciatus is a labeonin cyprinid from the Pahang River system in Peninsular Malaysia and the islands of Sumatra and Borneo. It has a red caudal fin with a thin dark stripe along each lobe, and longitudinal stripes formed by spots on the scales. Like other Labiobarbus it has two pairs of well-developed barbels and an extremely long dorsal fin, and the genus was known as Dangila for over 100 years.

Luciosoma spilopleura is a small cyprinid known only from Sumatra and the Indonesian part of Borneo, where it prefers fast-flowing headwater streams. The species is poorly known and is not present in the ornamental trade, although its name has been widely misapplied to other Luciosoma species for decades. The largest known specimen measured 81.9 mm, so it appears to grow much smaller than its congeners.