Indonesia

Acanthopsoides molobrion is a dwarf horse-faced loach from Borneo, Peninsular Malaysia and southern Thailand. Like others in the genus it lives in flowing, clear-water river channels over sand, fine gravel or mud, and needs a soft, sandy substrate because it spends some of its time completely buried. Several Acanthopsoides in the trade have proven very tricky to identify. This one has 10 to 15 mid-dorsal markings and three bands in the caudal fin.

Acanthopsoides robertsi is a dwarf horse-face loach from the Kapuas River basin in West Kalimantan, Indonesian Borneo. Unlike most of its congeners it is quite easily identified, being the only species with a dark, triangular marking in the caudal fin. Very similar fish have been collected further north in the Kayan and Sambas basins. Highly gregarious, it needs soft sand to bury in and is best kept in a group of six or more.

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 black lancer, Bagrichthys macracanthus, is a bagrid catfish described from Sumatra, Indonesia, and possibly endemic to that island. The name 'lancer' comes from the extended dorsal spine of several members of the genus. Fish from the Chao Phraya and Mekong once included in it were described as B. majusculus in 2002. A shy, nocturnal catfish of large, turbid rivers, it needs a dimly lit tank with plenty of hiding places and is territorial towards other bottom-dwellers.

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.

Barbodes banksi is a cyprinid from Peninsular Malaysia, Singapore and western Borneo, plus the Anambas and Natuna islands of Indonesia. It is tentatively considered distinct from the closely related B. binotatus, differing in a dark, wedge-shaped marking below the dorsal fin in place of a midlateral spot, though the two may be colour forms of a single species. Occasionally exported as bycatch, it lives in habitats from fast hill streams to canals and floodplain ponds.

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 false spanner barb, Barbodes kuchingensis, is a cyprinid apparently endemic to western Borneo, from Sarawak into the Kapuas system. It lives mainly in shallow, clear forest streams and is rarely exported, while subadult B. everetti and some populations of B. lateristriga are regularly traded under its name. B. kuchingensis sensu stricto has a prominent row of dark spots along the lateral line and a short streak extending from the upper part of the operculum.

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.

Barbonymus gonionotus is a large cyprinid with an enormous distribution across Southeast Asia, from the Mekong to Java and Sumatra. It inhabits larger, slow-moving rivers and their floodplains, moving into flooded forest to feed and spawn, and is increasingly found in man-made canals and lakes. Plain grey caudal and dorsal fins and pale yellow pelvic and anal fins separate it from congeners. Populations in Peninsular Malaysia appear to be introduced.

The tinfoil barb, Barbonymus schwanefeldii, is a large cyprinid found across much of Southeast Asia, from the Mekong to Borneo and Sumatra. Usually sold at 50 to 75 mm, it grows to 355 mm SL, and tinfoil barbs are among the species most often returned to shops having outgrown their aquarium. Selectively-bred 'golden' and 'blushing' strains exist, and the species has also been subjected to artificial dyeing.

Barbucca diabolica is a small 'scooter' loach from the upper-middle Kapuas basin in West Kalimantan, Indonesian Borneo, with one specimen from Johor. Barbucca spp. keep near-continuous belly contact with solid surfaces and often swim inverted or vertically. Most fish seen have red eyes and six dark body stripes, but several undescribed species exist and more than one may have been exported. Kottelat (2012) erected the family Barbuccidae for the genus.

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.

Betta albimarginata is a small mouthbrooding labyrinth fish that appears endemic to the Sebuku River drainage in East Kalimantan, Indonesian Borneo. It lives among marginal plant roots and leaf litter in forest streams only 5 to 10 cm deep. With B. channoides it forms the Betta albimarginata group, and the two look very similar: in B. albimarginata the unpaired fins have a broad white distal band and a broad dark submarginal band around a plain red inner portion.

Betta antoni is a mouthbrooding labyrinth fish that appears endemic to the lower Kapuas basin in West Kalimantan, Indonesian Borneo. Known as Betta sp. 'Sanggau' before its description, it belongs to the Betta akarensis group. It inhabits quiet margins and still pools in clear, flowing forest hill streams, and live fish show blue iridescence on the body scales and a distinct black lower lip.

Betta balunga is a mouthbrooding labyrinth fish from Borneo, found from Tawau in Sabah, Malaysia, south to the Sebuku and Mahakam basins in Indonesia. A member of the Betta akarensis group, it has a reddish-orange iris in life. In the Sebuku it lives in very shallow forest streams among roots and leaf litter, and in the Mahakam basin in sluggish blackwater streams among submerged marginal vegetation.

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.

Betta brownorum is a small bubble-nesting labyrinth fish endemic to Borneo, found in southern and western Sarawak and in West Kalimantan. A member of the B. coccina group, it is a stenotypic inhabitant of peat swamp forests and their blackwater streams. Both sexes carry a large iridescent green lateral blotch on a reddish-magenta body, though patterning within the group can be similar and confusingly variable.

Betta burdigala is a small bubble-nesting labyrinth fish endemic to the island of Bangka, off the east coast of Sumatra, Indonesia. A stenotypic inhabitant of peat swamps and blackwater streams, it belongs to the B. coccina group and is most similar to B. uberis. The species is exceptionally rare in the hobby, and many fish traded or pictured under its name are B. uberis or another congener.

The snakehead betta, Betta channoides, is a small mouthbrooding labyrinth fish from the Mahakam basin in East Kalimantan, Indonesian Borneo. It inhabits shallow forest streams with brownish, acidic water, among leaf litter and marginal plant roots. With the very similar B. albimarginata it forms the Betta albimarginata group, and displaying males are scarlet, with an almost entirely red dorsal fin edged by a thin white band.

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 dimidiata is a small mouthbrooding labyrinth fish that appears endemic to the upper Kapuas drainage in West Kalimantan, Indonesian Borneo. It is often confused in the trade with B. krataios, formerly B. sp. 'Kapuas', but the caudal fin separates them: rounded in B. krataios, spade-shaped and more extended in adult B. dimidiata. It inhabits shaded forest swamp streams and pools, some only a few centimetres deep.

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 enisae is a paternal mouthbrooding labyrinth fish known only from parts of the River Kapuas basin in West Kalimantan, Indonesian Borneo. A member of the B. pugnax complex, whose species are notoriously difficult to tell apart, it has transverse bars in the caudal fin. Populations differ in colour and pattern and are often labelled with collection details such as Putussibau or Sentarum. It inhabits cool, shaded forest streams and swamp pools stained with humic acids.

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 foerschi is a paternal mouthbrooding labyrinth fish from a handful of localities in Central and West Kalimantan, Indonesian Borneo. It lends its name to the B. foerschi group, whose members have iridescent blue or green unpaired fins and two reddish-yellow bars on the opercle. Fish traded as B. foerschi are often the closely-related B. mandor, and the two can be difficult to tell apart.

Betta hendra is a small bubble-nesting labyrinth fish known only from the Sabangau peat swamp forest near Palangkaraya, Central Kalimantan, Borneo. A member of the B. coccina group, it has bright iridescent green flanks and fins where most of its relatives are red. It has been traded as B. sp. 'Sengalang/Palangkayara' and B. sp. 'Sebangua'. The type locality is still, shaded blackwater with a pH around 4.0.

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.

Betta ideii is a large paternal mouthbrooding labyrinth fish from southern South Kalimantan and Pulau Laut, Indonesian Borneo. Traded as B. sp. 'Laut' before its description, it belongs to the B. unimaculata complex and grows to 110 mm SL. It looks very similar to its closest relative B. patoti but lacks dark vertical bars on the flanks, and adult males are much darker.

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 krataios is a paternal mouthbrooding labyrinth fish that appears endemic to the lower River Kapuas basin in West Kalimantan, Indonesian Borneo. Traded as B. sp. 'Kapuas' before its description, it is sometimes confused with B. dimidiata, the other member of the B. dimidiata group. The two are easily told apart since the caudal fin is rounded in B. krataios and spade-shaped and more extended in B. dimidiata.

Betta lehi is a paternal mouthbrooding labyrinth fish endemic to Borneo, in southwestern Sarawak and the lower River Kapuas basin in West Kalimantan. A member of the B. pugnax complex, it has green iridescent scales on the opercle and body and a light blue iridescent band on the anal fin. It inhabits forest peat swamps, acidic clearwater swamps and associated streams, where the pH can be between 3.0 and 5.5.

Betta mandor is a paternal mouthbrooding labyrinth fish from near Mandor and Anjungan in the lower Kapuas basin, West Kalimantan, Borneo. Known as B. sp. 'Mandor' or B. sp. 'ninja' before its description, it belongs to the B. foerschi group. Males are black and females brown, with twin red bars on the opercle. It is sometimes traded as B. foerschi, and the two can be difficult to tell apart.

Betta midas is a stout-bodied labyrinth fish from the lower Kapuas basin in West Kalimantan, Indonesian Borneo, and may also occur in western Sarawak. It has been traded as B. anabatoides in the past, and most images of it are labelled as such. It has gold iridescent scales on the opercle, belly and body. The paratype series came from a blackwater river in peat swamp forest with a pH of 4.1.

Betta miniopinna is a small bubble-nesting labyrinth fish endemic to Bintan Island, Indonesia, where it is known from a few northern localities. A dark member of the mostly red B. coccina group, it is most similar to B. persephone. Development for tourism and rubber plantations has left it restricted to a few pockets of primary peat swamp forest, and it has been listed as Critically Endangered on the IUCN Red List since 1996.

Betta ocellata is a large paternal mouthbrooding labyrinth fish from Sabah, northeastern Borneo, and the Sebuku River basin in East Kalimantan. A member of the B. unimaculata complex, it grows to 90 mm SL and has a pointed, slightly conical head. It has been collected from clear flowing streams, elevated headwater pools, turbid forest streams, ox-bow lakes and ponds in oil palm plantations.

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 patoti is a large paternal mouthbrooding labyrinth fish from East Kalimantan, Borneo, described from the Mangar River near Balikpapan. A member of the B. unimaculata complex, it grows to 100 mm SL and has 10-14 dark vertical bars on the lower body. Colour varies with locality, from blackish-barred fish around Balikpapan to more reddish ones further north.

The spotted betta, Betta picta, is a small paternal mouthbrooding labyrinth fish known only from Java, Indonesia. It lends its name to the B. picta complex and has iridescent yellow-gold opercle scales. It is usually found in quiet margins and still pools of clear, flowing hill streams, but has also been collected from roadside ditches and water tanks.

Betta pinguis is a paternal mouthbrooding labyrinth fish known only from the middle and upper Kapuas watershed in West Kalimantan, Indonesian Borneo. A member of the B. akarensis group, it has a relatively stocky body and dense dark markings on the opercle below the postorbital stripe. The type specimens came from a small, slightly tannin-stained stream in degraded forest, where B. dimidiata and B. enisae also occur.

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 rutilans is a small, deep red labyrinth fish from peat swamps near Anjungan in West Kalimantan, Borneo, Indonesia. Known in the hobby as B. sp. 'Anjungan' before its description, it belongs to the B. coccina group, whose members can be hard to identify because their patterning is similar and confusingly variable. B. rutilans has a uniformly deep red body with no midlateral blotch. A bubble-nester, it lives in blackwater streams where the pH can be as low as 3.0 or 4.0.

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.

Betta sp. 'Antuta/Bulungan' is an undescribed mouthbrooding labyrinth fish from Bulungan Regency in East Kalimantan, northern Indonesian Borneo. It appears to be a member of the B. unimaculata complex, and its habitat is thought to be flowing highland streams. Adult size is unconfirmed but likely to be 90 to 100 mm. Relatively peaceful, it can be kept in a group in a tank of sufficient size with plenty of hiding places.

Betta spilotogena is a mouthbrooding labyrinth fish from Bintan and Singkep islands in the Riau Islands province of Indonesia. It inhabits shaded freshwater swamps and streams with clear or lightly tannin-stained water less than a metre deep, alongside B. edithae, B. miniopinna and B. fusca. A member of the B. waseri group, it has a single dark, pear-shaped blotch on the throat that is not joined to the black lower lip.

Betta taeniata is a mouthbrooding labyrinth fish endemic to Borneo, known from southern Sarawak in Malaysia and northern West Kalimantan in Indonesia. It is usually associated with clear, flowing hill streams, where it lives in quiet marginal zones and still pools among leaf litter and gravel. A member of the B. picta group, it has a yellowish body and fins and a blackish head. Populations such as Sri Aman, Serian and Kapuas are often labelled by locality to preserve pure bloodlines.

Betta uberis is a small bubble-nesting labyrinth fish from peat swamp forests in Central and West Kalimantan, Borneo, Indonesia. Most records come from between the lower Arut and Kumai rivers near Pangkalan Bun. Known to aquarists as Betta sp. 'Sukadana' or B. sp. 'Pangkalanbun' before its description, it belongs to the B. coccina group and is named for its high count of 14 to 17 dorsal-fin rays, which also separates it from its nearest neighbour in the group, B. hendra.

Betta unimaculata is a large mouthbrooding labyrinth fish from the upper Kayan and Mahakam river drainages in East Kalimantan, Borneo, Indonesia. Growing to around 115 mm SL, it has been collected from clear, flowing streams, elevated headwater pools and more turbid forest streams. Populations differ in colour and pattern and will hybridise, so they are labelled by locality and should never be kept together. Fish from 'Tawau' once thought to be this species have been described as B. ocellata.

The mosquito rasbora, Boraras brigittae, is a miniature cyprinid that appears to be endemic to southwestern Borneo. It inhabits blackwater streams and pools associated with forest peat swamps, where the water is very soft and acidic. The congener B. urophthalmoides is often traded under its name, but B. brigittae is larger, lacks a distinct dark blotch at the caudal peduncle and has brighter, more uniformly red patterning. Striped males of B. merah have led to speculation that the two are the same species.

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.

Boraras merah is a miniature cyprinid from southern Borneo, described from the Jelai Bila river basin near Sukamara in Central Kalimantan, Indonesia. Sometimes sold as the 'phoenix rasbora', it lacks colour in much of the body, with the red pigmentation concentrated around dark markings that tend to form spots or blotches. Fully-striped males have led to speculation that it is the same species as B. brigittae, though Kottelat (2013) argued for two species.

The bumblebee goby, Brachygobius doriae, is a small goby from western Borneo and the Natuna Islands, described from Sarawak. Among the more frequently traded members of the genus, it is often misidentified as B. nunus or B. xanthozonus and is most easily confused with B. sabanus. It lives in fresh and brackish water in lowland coastal habitats such as mangrove swamps, estuaries and tidal streams. It is best kept in a species-specific set-up.

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 olive flathead gudgeon, Butis amboinensis, is a nocturnal ambush predator from the eastern Indian Ocean to the West Central Pacific. It inhabits brackish estuaries, lagoons and mangroves, entering tidal freshwater rivers to an extent, and often aligns itself with solid surfaces or swims upside-down. It is occasionally exported as bycatch and differs from congeners in lacking enlarged outer teeth and scales on the cheek. It is territorial and should probably be kept singly.

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.

The walking catfish, Clarias batrachus, is a large air-breathing catfish. In the strict sense it is known only from Java, and the walking catfishes of mainland Asia belong to other species. It can move across land on its stiff pectoral spines provided it stays damp, so a tightly fitting cover is essential. Walking catfishes are highly predatory and tolerate a very wide range of conditions, and they have become pests in several countries where they were introduced for farming, most notably the southern US. Most fish in the trade are albino or leucistic aquarium variants.

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.

Crossocheilus nigriloba is a cyprinid endemic to Borneo, known from the Kapuas, Belayan and Mahakam rivers in Indonesian Kalimantan. Rarely seen, it is among the near-identical congeners traded as 'Siamese algae-eater' or 'SAE' but is simple to identify: the lower caudal-fin lobe carries dark pigment suffused with red, which gave rise to the trade name 'penguin flying fox'. The lateral stripe breaks into blotches when the fish are sparring, stressed or sleeping.

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 janthochir is a cyprinid endemic to Borneo, known from West and Central Kalimantan in Indonesia. It inhabits black water streams and rivers associated with ancient forest peat swamps, where the water is very soft and acidic. Red markings in the dorsal and caudal fins plus a dark lateral stripe make it easy to identify. Specialised shops stock it from time to time, and it also turns up as bycatch among wild fish from Kalimantan.

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 endecanalis is a cyprinid apparently endemic to the Kapuas River basin in West Kalimantan, Borneo, including the Danau Sentarum lakes. A whitish base body colour and 8 (rarely 7) branched anal-fin rays distinguish it from congeners, and its placement in Desmopuntius was only tentative. Its habitat is unconfirmed, but related species are associated with peat swamps and black water streams.

Sometimes traded as the 'boomerang barb' or 'Foersch's fire barb', Desmopuntius foerschi is a cyprinid from East and Central Kalimantan, Borneo. Extra dark blotches between the second, third and fourth vertical bars, and a mark at the rear of the dorsal-fin base, set it apart from other vertically-striped congeners. It probably inhabits peat swamps and associated blackwater streams, and information on its range is scarce.

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 snakeskin barb, Desmopuntius rhomboocellatus, is a cyprinid endemic to southern Kalimantan, the Indonesian portion of Borneo. It has been recorded from several river systems including the Kapuas, Kepayang and Barito. It most often inhabits peat swamps, black water streams and other still waters with submerged plants and dense riparian vegetation.

Desmopuntius trifasciatus is a cyprinid from Borneo, described from the Kapuas basin in West Kalimantan and also known from southern Sarawak. Like D. gemellus and D. johorensis, juveniles have 4 dark vertical bars, and fish over 40 mm have 3 or 4 broad lateral stripes, the central one broadest. It may also be confused with Striuntius lineatus.

Eirmotus insignis is a small cyprinid known only from the Kapuas basin in West Kalimantan, Borneo, and Belitung Island off Sumatra. It inhabits shady, slow-moving rainforest streams and swamps with dense vegetation. One of four similar species in the genus, it is traded alongside E. octozona as the 'false eight-banded barb' and is told apart mainly by the black markings on its dorsal fin.

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.

Gastromyzon ctenocephalus is a hillstream loach from western Borneo, known only from headwaters of the Sarawak and Sambas rivers. One of the more commonly traded members of the genus, it turns up in mixed shipments labelled 'Borneo sucker', 'Hong Kong pleco' or 'butterfly loach'. It is sometimes misidentified as G. punctulatus, which has yellow fins and a lighter, less intensely spotted body.

Gastromyzon lepidogaster is a hillstream loach from northern Borneo and the most widely-distributed member of the genus. It occurs in Sabah, Brunei and East Kalimantan. Colour is variable: large adults may be bright green, orange or barred, and can apparently change from barred to plain in a few seconds. It is occasionally available in the trade, where the orange form is particularly sought after.

Gastromyzon sp. 'SK01' is an undescribed hillstream loach known only from the Sungai Jorong in South Kalimantan, Indonesian Borneo. The Jorong is part of the upper Barito drainage. The 'SK' code refers to South Kalimantan, home to several unidentified members of the genus. Based on colour pattern it appears similar to members of the G. ridens group. It has occasionally been maintained by private collectors, and like its congeners it lives in swift, shallow streams with clear, oxygen-saturated water.

Gastromyzon sp. 'SK02' is an undescribed hillstream loach from the Sungai Amandit headwaters in South Kalimantan, Indonesian Borneo. The Amandit is a tributary of the Barito basin in the Meratus mountain range. Based on colour pattern this species appears similar to members of the G. ridens group, and it has occasionally been maintained by private collectors. Like its congeners it needs clean, well-oxygenated water with strong flow.

Gastromyzon sp. 'SK03' is an undescribed hillstream loach from a tributary of the Sungai Riam Kiwa in South Kalimantan, Indonesian Borneo. The Riam Kiwa feeds the Martapura, a major tributary of the Barito. The 'SK' code refers to South Kalimantan, home to several unidentified members of the genus. Based on colour pattern it appears similar to members of the G. ridens group, and it has occasionally been maintained by private collectors.

Gastromyzon zebrinus is a hillstream loach known only from the upper Sambas River in West Kalimantan, Indonesian Borneo. Its black body carries 11-13 thin cream bars on the dorsal surface. It forms a pair of cryptospecies with G. stellatus, separated from it by an outcrop of the Müller range, and intermediate colour patterns mean the two are often confused. It is one of the more commonly-traded members of the genus.

Gymnochanda filamentosa is a small glassfish known from Johor in southern Peninsular Malaysia and the Kapuas system in West Kalimantan, Borneo. Males carry filamentous dorsal and anal-fin rays, and the body is transparent to translucent yellowish-brown in life. It occurs in swampy, acidic waters over silt and peat, and has appeared in the ornamental trade but is evidently delicate and recommended only to experienced aquarists.

Gymnochanda verae is a small glassfish known only from the Gantung area of Belitung Island, in Indonesia's Bangka-Belitung Islands province. Mature males have extended anal and second dorsal fins forming a triangular profile, with the outer parts of those fins and of the caudal-fin lobes carmine red in life. Females have neither elongated rays nor colour. It has appeared in the ornamental trade but is evidently delicate and recommended only to experienced aquarists.

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.

The saddle-back loach, Homaloptera orthogoniata, is a 'lizard' loach endemic to Borneo, known from rivers in Sarawak and Kalimantan. It was historically said to occur across much of Indochina. It is rare in the hobby, and most images online and in the literature show H. confuzona or H. parclitella. It always has three large, saddle-shaped markings on the back, the third between the dorsal and caudal fins.

Homalopteroides nebulosus is a small hillstream loach described from the Sok River in northern Peninsular Malaysia and since recorded from Borneo. Poorly known in the aquarium hobby, it may never have been exported for the ornamental trade. Its eyes sit in a comparatively raised position on the head, as in H. tweediei, but it has more lateral line scales. Little is known of its habitat, which is presumed to be swiftly-flowing streams and headwaters.

Homalopteroides stephensoni is a hillstream loach from Borneo, recorded from Kalimantan in Indonesia and from Sabah and Sarawak in Malaysia. Poorly known in the aquarium hobby, it may never have been exported for the ornamental trade. Originally described in Homaloptera, it was placed in Balitoropsis by Kottelat (2012), who subsequently followed Randall and Page (2012) in treating it as a Homalopteroides. Like its congeners it inhabits swiftly-flowing, clear, oxygen-saturated streams.

Homalopteroides tweediei is a small hillstream loach from Peninsular Malaysia, the Mekong system and West Kalimantan in Indonesian Borneo. It is often confused with the congener H. smithi. Rainboth (1996) found it less likely to occur in riffles or runs than other members of the genus, and it shows a preference for moderately-flowing stretches of clear, oxygen-rich streams among patches of live or dead vegetation.

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.

Hypergastromyzon humilis is a small hillstream loach known only from the Melawi basin of the Kapuas system in West Kalimantan, Indonesian Borneo. Not traded specifically, it sometimes turns up as bycatch among shipments of wild-collected Gastromyzon. It is told from those by its small mouth without papillae, and from H. eubranchus, the only other species in the genus, by its 7-8 cream-coloured dorsal bars.

The empire gudgeon, Hypseleotris compressa, is an eleotrid from northern and eastern Australia and southern New Guinea. Breeding is rarely achieved in aquaria because of its complex amphidromous strategy: adults spawn in freshwater streams, but the larvae are washed downstream to the sea and develop there. Plenty of cover and broken lines of sight let weaker individuals escape the attention of dominant fish.

The threadfin rainbowfish, Iriatherina werneri, is a small rainbowfish from southern New Guinea, Cape York in Queensland and the Northern Territory. Although widely traded and produced on a commercial scale, it is quite delicate with rather specific care requirements and is not a recommended beginner's fish. Easily outcompeted for food, and with long-finned males that some common species nip, it is best kept alone or with fishes of comparable size and disposition.

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 hipporhynchos is a small cobitid loach known only from Central Kalimantan in Indonesian Borneo. It lives in slow-moving forest streams with clear, tannin-stained water over white sand, where it rests on the substrate or dives into it, so it must be given a soft sandy substrate. The largest member of the genus, it differs from its congeners in having papillae covering the lips, barbels and lobes of the mouth.

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.

The fire eel, Mastacembelus erythrotaenia, is a spiny eel recorded from Laos, Vietnam, Cambodia, Thailand, Malaysia and Indonesia. It usually inhabits sluggish lowland waters including floodplains and slow-moving rivers, and is also a food fish in its native countries. In the aquarium it hides away during the day and often buries itself, so it needs a sand substrate, plenty of cover and a close-fitting hood.

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 saravacensis is a nemacheilid loach from Borneo, recorded from drainages in Sarawak (Malaysia) and West Kalimantan (Indonesia). It inhabits clear, tea-coloured forest streams with low mineral hardness and pH. Rare in the aquarium hobby, it may only have appeared as bycatch, and it carries 13-17 irregular dark blotches along the lateral line with a similar number of saddles across the back.

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.

Nemacheilus spiniferus is a nemacheilid loach from Borneo, recorded from Sarawak, Brunei and Kalimantan, plus the Natuna and Anambas islands. It is most common in shallow, flowing forest streams with clear to slightly tannin-stained water. A member of the N. selangoricus group, it is rare in the aquarium hobby and differs from N. selangoricus in its 10-13 irregularly-shaped dark bars.

Neohomaloptera johorensis is a tiny balitorid loach from Peninsular Malaysia, found mainly in peat swamps and associated blackwater streams. Its small adult size and orange to reddish-brown colour make it difficult to confuse with any other balitorid. The water in its habitat is stained brown, with negligible mineral content and pH as low as 3.0 or 4.0. It needs well-oxygenated water free of organic pollutants.

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.