Rasboras & relatives

Appears to be endemic to southwestern Borneo though occurence records are scant. Type locality is 'Bandjarmasin', a port town in the Indonesian province of Kalimantan Selatan (South Kalimantan), and following Kottelat (1991) it's range extends westwards as far as the Jelai Bila river basin, near the town of Sukamara, where it's said to occur sympatrically with the congener B. merah. Boraras was erected in 1993 in order to separa...

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.

Appears endemic to southern Borneo. The type specimens were collected from the Jelai Bila river basin at Nataik Sedawak, presumably a settlement of some kind, near the town of Sukamara in the Indonesian province of Kalimantan Tengah (Central Kalimantan). Its range extends westwards from the Jelai Bila watershed whereas that of the congener B. brigittae, with which it may occur sympatrically there (see 'Notes'), extends east.

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.

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.

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...

This species is very rare in the trade and is normally imported only as bycatch among shipments of other fishes. It can be told apart from its well-known congener B. dorsiocellata by a combination of characters as follows: lateral line complete (25-30 pored scales vs. 4-9); more scales in the lateral row (29-32 vs. 25-27); larger adult siz...

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.

This species was described from 'Johore River, Segamat, Malaysia', which corresponds to Segamat District within the the Johor River watershed, Johor state, southern Peninsular Malaysia, but the type specimens were obtained via a Singapore wholesaler so it's possible that a mistake was made as there exist no other records of the species in Peninsular Malaysia. It's also been recorded from the Kapuas drainage...

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...

The identity of this species was unclear for a number of decades prior to its redescription by Ng and Kottelat (2013). The confusion originated with Brittan (1954) who misidentified specimens of R. tornieri as R. dusonensis and was exacerbated by Alfred (1963) who concluded that the holotype of R. dusonensis was conspecific with R. myersi.

Type locality is 'Central Sumatra, Indonesia', with additional records existing from Cambodia (Mekong drainage), Peninsular Malaysia (Perak River), Sumatra (from the Siak River, Riau province to the Musi River, South Sumatra (Sumatera Selatan) province) and Borneo (south and westwards from the Belait river basin in Brunei Darussalam to the Sambas drainage in West Kalimantan (Kalimantan Barat) province, Indonesia and probably in Sarawak, Malaysia).

These are still regarded as valid by some authorities although it's widely accepted that they represent variants of R. vaterifloris due to a lack of type material hindering conclusive study. Rasboroides nigromarginata (Meinken, 1956) has also been used to refer to a reddish form in which males differ from other populations in possessing dark fin margins, but the name is currently considered synonymous with R. vaterifloris by most sources despite the fish being rediscovered in 2010.

This species occurs in several colour forms depending on collection locality with some exhibiting more intense pigmentation in the fins or an additional reddish lateral stripe, for example. It's sometimes said to closely resemble and occur sympatrically with Rasbora agilis, but that name is currently considered a junior synonym of the congener Trigonopoma pauciperforatum. R. agilis had previously been us...

This species is also sold as the 'redline' rasbora which is something of a misnomer as in reality the colour of the lateral stripe that gives rise to the name can vary from deep orange to golden depending upon the collection locality of the fish as well as diet, condition, and even mood. Some specimens also have a second, darkish stripe beneath the other which seems to vary in length and intensity depending on a similar array of factors. Older fish tend to possess a greater degree of black edging to the scales, especially in the ventral portion of the body.

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.

T. hengeli is sometimes seen for sale with the trade name of 'glowlight rasbora' due to the distinctive orange patterning on the posterior part of the body but we've refrained from using that name here because it's also commonly applied to Trigonopoma pauciperforatum. It can be confused with the similar-looking T. heteromorpha and T. espei although on close inspection they're actually quite easy to tell...

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...

R. borapetensis is one of the more commonly-encountered rasboras in stores and is particularly recommended for newcomers to the hobby. While it can appear a little plain or 'washed' of colour when seen on sale once settled and in good condition it is an eye-catching little fish that often schools quite closely. It's sometimes sold with the alternative trade names of black-line or magnificent rasbora. R. rubrodorsalis is a very similar-looking congener that occurs sympatrically...

R. kalochroma exhibits variable patterning across its range according to locality with some forms possessing a line of spot-like markings connecting the two dark blotches on the flanks and others more intense body colouration. Juveniles are sometimes confused with Boraras maculatus and adults with the similarly-patterened R. elegans although the latter is easy to identify by its overall silver, as opposed to pinkish/reddish, colouration. The only congener for which it may be genuinely mistake...

This species is also traded as 'Bornean redfin rasbora', 'sunshine rasbora' and 'dwarf volcano rasbora' and first appeared in the hobby during the latter part of 2010. It can be told apart from all other members of the genus by a combination of the following characters: possession of small tubercules on the dorsal surface, posterior to theand continuing onto the upper part of caudal fin, visible as an irregular 'crest' when a specimen is viewed laterally; ...

Rainboth's 'Fishes of the Cambodian Mekong' characterised members of Rasbora by possession of an unbranched, non-spiny firstray and seven soft dorsal rays, origin of thein the middle of the body, five branchedrays, a small mouth not extending below the eye and a lack of barbels. It's long been recognised as a polyphyletic lineage as noted by Kottelat (1999) amongst others, and in 2010 the results of a phylogenetic analysis by T. Y. Liao et al. suggested a number of changes in...

This species is rarely seen in the trade and little has been written regarding its captive care. It's possible that several colour forms may exist depending on collection locality. Rainboth's 'Fishes of the Cambodian Mekong' characterised members of Rasbora by possession of an unbranched, non-spiny firstray and seven soft dorsal rays, origin of thein the middle of the body, five branchedrays, a small mouth not extending below the eye and a lack of barbels. It's long b...

R. rubrodorsalis occurs sympatrically with the very similar-looking R. borapetensis over some of its natural range but is much the rarer of the two in the aquarium hobby. They are easily distinguishable from one another because R. rubrodorsalis has a bright red blotch in thewhilst in R. borapetensis the dorsal is colourless and only the base of the is coloured red. This species is sometimes sold under the erroneous name(s) R. beauforti or R. sp. cf. beauforti, probably because it was picture...

This species was described in 1999 and may still occasionally be seen on sale under the incorrect names R. reticulata or R. cf. reticulata as well as the trade name 'volcano rasbora'. The real reticulata is endemic to the small island of Nias which lies off Sumatra's northwestern coast and is virtually inaccessible to fish collectors so is unlikely to be in the hobby although it may have been exported on a couple of occasions. It's a deeper-bodied fish and does not exhibit th...

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...

This striking species may also be seen on sale with the trade name of 'red scissortail'. It can be distinguished from the similar-looking R. trilineata by the presence of orange/red colouration in the with other diagnostic features including black tips to the caudal lobes, 11-12 predorsal scale rows and a dark reticulated pattern to the edges of the scales. The 'scissortail' moniker is derived from the characteristic twitching motion of the when the fish is at rest. Rainb...

This species is not often exported which is a shame as it makes an elegant, peaceful resident of the larger community tank. It can be easily distinguished from similar-looking congeners such as R. einthovenii and R. jacobsoni by examining the dark lateral stripe that extends lengthways along the body of the fish as in R. cephalotaenia it is composed of a series of dark spots whereas in the other species it forms a continous solid line. Rainboth's 'Fishes of the Cambodian Mekong&#039...

This fish may well be a form of R. dandia itself but in the absence of scientific confirmation we list it with a 'cf' abbreviation for the time being. It appears to be widely available in the trade but is often (mis)identified as R. wilpita, a species now confirmed as endemic to a small number of streams in Sri Lanka and which is probably much rarer in the hobby than previously thought. Valenciennes initially described Leuciscus dandia as a new species from Sri Lanka in 1844 but the...

This is one of the more commonly-seen rasboras in the hobby and is ideal for the medium-sized community set-up. It shares some close similarities with R. jacobsoni but can be most easily identified by the fact it lacks dark reticulated scales above the lateral stripe. This stripe also has noticeably more uneven or "crinkly" edges in R. einthovenii than in R. jacobsoni or indeed any other species of laterally-striped Rasbora. A further distinguishing combination of characters for both t...

This species is not especially popular in the hobby and is only infrequently seen on sale. It is clearly distinguishable from similar-looking members of the genus by lacking a dark stripe along the lateral line. Instead it possesses two spot-like markings on each flank, one below theorigin and lateral line and another at the caudal peduncle. The intensity of these can vary depending on the collection locality of the fish and they can be quite faint in some forms. There is also a third, smaller m...

It is unclear if this species has been available in the aquatic trade as collections from its native waters only occur sporadically, therefore we have based much of the information here on experience with its closest relative R. kalochroma. These two are almost identical in appearance and share some meristic features but R. kottelati possesses an additional, oval-shaped dark blotch on the caudal peduncle, lacks the stripe in the middle of the seen in R. kalochroma and is consequently easy to dis...

In much of the literature this species is pictured with the invalid name R. paviei, due to an issue with spelling which was corrected by Kottelat (2005), and the common name 'sidestripe rasbora' although the latter has yet to find popularity in the aquarium hobby. There are a number of similar-looking species including R. sumatrana, R. hobelmani and R. laticlavia and it can be problematic to separate members of this 'group'. If the collection locality of the fish is known ide...

R. sarawakensis is poorly-documented in the aquarium literature and we're not even sure if it has been exported for the hobby although it may be worth looking out for among shipments of wild fish from southern/western Borneo. We find this a little odd as it is an attractive, very peaceful little fish that would suit many home aquaria and is apparently quite common across its natural range. Rainboth's 'Fishes of the Cambodian Mekong' characterised members of Rasbora by poss...

This popular species is also known as the 'three-lined' rasbora and provided a large enough tank is available it is an excellent choice for those new to the hobby. The 'scissortail' moniker is derived from the characteristic twitching motion of the when the fish is at rest. It can be distinguished from the similar R. caudimaculata by lacking red colouration in the and from R. spilocerca by its much larger size. Several geographical forms appear to exist as some wild populatio...