Mae Klong basin

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 Mae Klong chameleon catfish, Acrochordonichthys septentrionalis, is an akysid from western Thailand, possibly endemic to the Mae Klong drainage. It differs from other members of the A. ischnosoma group in its almost uniformly cream body with a few small brown spots, though colouration in the genus is variable. Like its congeners it can secrete a milky substance from the axillary pore when stressed, and this can quickly kill other fishes in an aquarium.

The dwarf chain loach, Ambastaia sidthimunki, is a small botiid loach from the Mae Klong basin in western Thailand and the Ataran drainage in Myanmar. Older records from the Yom River, Laos and Cambodia refer to A. nigrolineata. Gregarious, it should be kept in a group of at least five or six and preferably ten or more, and reports conflict on whether it stays peaceful with sedentary or long-finned fishes.

The princess carplet, Amblypharyngodon chulabhornae, is a small cyprinid from Thailand and the Mekong system in Laos, Vietnam and Cambodia. It favours wetlands and marginal zones with little water movement and plenty of aquatic and floating vegetation,. Almost unknown in the hobby, it turns up as occasional bycatch among shipments of other fishes. A very peaceful schooling fish, it should be kept in a group of at least 8 to 10.

Badis khwae is a badid that appears to be endemic to the Khwae Noi River basin in western Thailand, close to the border with Myanmar. It is most easily confused with B. ruber and B. siamensis, but lacks the rows of dark spot-like markings both have on the flanks. Its restricted range means it is unlikely ever to be available in large numbers. It lives in small forest streams with sluggish to moderate flow, usually in marginal areas or still pools.

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.

The red-tailed tinfoil barb, Barbonymus altus, is a large cyprinid from Thailand, Laos, Cambodia and Vietnam. One of two species traded as 'tinfoil barb', it is usually sold at 50 to 75 mm with little information on its eventual size, and long-term care is beyond the resources of most hobbyists. Natural fish lack the black stripe along each caudal-fin lobe seen in B. schwanefeldii, and adults have a golden or bronze hue.

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.

Batasio tigrinus is a small bagrid catfish that appears endemic to the Khwae Noi basin, often called the River Kwai, in western Thailand. The Khwae Noi is part of the larger Mae Klong watershed. Like its congeners it is an obligate inhabitant of shallow, fast-flowing, highly-oxygenated headwater streams, and it is largely unsuitable for the 'general' community aquarium.

The Siamese fighting fish, Betta splendens, is a labyrinth fish from central Thailand, native to rice paddies, swamps, ditches and other still waters. The wild form is rarely seen in the hobby, but countless ornamental strains exist that vary tremendously in colour, finnage and quality. Its care requirements and disposition mean it is best kept alone, and it is not recommended for the standard community aquarium.

Boraras urophthalmoides is a miniature cyprinid from southern and central Thailand, Cambodia and Vietnam, including the moats of Angkor Wat. It inhabits shallow, clear, vegetated swamps, marshes, floodplains and rice paddies. Some populations develop an orange-red stripe that leads to confusion with B. brigittae, but B. urophthalmoides is smaller, with a distinct round, dark blotch on the caudal peduncle and a long, unbroken lateral stripe. It is sometimes sold as the 'exclamation-point rasbora'.

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 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.

Discherodontus ashmeadi is a cyprinid apparently native to the Mae Klong and Mekong river basins in Thailand, Laos and Cambodia. The type species of its genus, it inhabits clear, fast-flowing minor rivers and forest streams. Like its congeners it is notoriously delicate and difficult to ship: it goes into shock and loses scales very easily when removed from the water, and damaged areas tend to become infected.

Discherodontus halei is a cyprinid with an apparently disjunct range: Pahang in Peninsular Malaysia, and the Mae Klong and Chao Phraya in Thailand. It inhabits clear, fast-flowing minor rivers and forest streams, and orange pigmentation in the dorsal and caudal fins helps separate it from congeners. Like others in the genus it is notoriously delicate and difficult to ship, losing scales very easily when removed from the water.

Discherodontus schroederi is a cyprinid native to the Mae Klong and Chao Phraya river basins in Thailand. Said to be the hardiest member of the genus, it is rarely collected for the aquatic trade, presumably because it is the least colourful of the Thai species. Juveniles can be confused with D. ashmeadi, but its dark dorsal blotch fades to a thin distal band with age, and its barbels are noticeably longer than in other members of the genus.

The red-tailed black shark, Epalzeorhynchos bicolor, is a cyprinid native to central and western Thailand, in the Mae Klong and Chao Phraya basins. Declared extinct in 1996, it was found again in 2011 and 2014 and is considered critically endangered, while all fish in the trade are commercially produced. It becomes increasingly territorial as it grows, especially towards similar-looking species, and can live for over 15 years.

The rainbow shark, Epalzeorhynchos frenatum, is a cyprinid reportedly native to Thailand, Laos and Cambodia. Recorded from the Mae Klong, Chao Phraya and Mekong basins, many of its wild populations have dwindled or vanished, and large numbers are farmed for the trade, including an albino and an anerythristic form sometimes misidentified as E. munense. It becomes increasingly territorial as it grows and can live for over 15 years.

The striped flying barb, Esomus metallicus, is a cyprinid found from the Salween basin in Myanmar east across Thailand to Laos and Cambodia. It is abundant over most of this range and moves into rice paddies and other flooded ground at the onset of the wet season, returning to permanent water when the flooding recedes. Its lateral stripe grows more intense towards the tail and ends at the caudal-fin base.

The false SAE, Garra cambodgiensis, is a cyprinid from the Mekong, Chao Phraya and Mae Klong basins and northern Peninsular Malaysia. It is still traded as Garra taeniata and is often confused with the Crossocheilus species sold as 'Siamese algae eater'. In this species the dark lateral stripe ends at the caudal peduncle, and a sucker formed by the lower lip is present. It inhabits swiftly-flowing headwaters and tributaries.

The sucking 'loach', Gyrinocheilus aymonieri, is a stream fish from the Mae Klong, Chao Phraya, Mekong and Dong Nai basins in Indochina. Often sold as a loach, or as the 'Indian' or 'Chinese' algae eater, it is neither a loach nor native to either country. It can live for more than 15 years and is largely unsuitable for the general community aquarium. It is farmed in large numbers, including albino, 'golden', 'piebald' and 'short-bodied' forms.

Homaloptera bilineata is a 'lizard' loach from the Sittaung and Salween basins of Myanmar and tributaries of the Mae Klong in western Thailand. Uniquely in the genus, the dark markings running back from the snout form two distinct stripes meeting at the dorsal fin and do not form saddles. An obligate dweller of swift, oxygen-saturated streams, it needs clean, well-oxygenated water and is best kept in a group of six or more.

Homaloptera confuzona is a 'lizard' loach mostly recorded from the Mekong basin in Laos and Cambodia, and from smaller drainages in southern Thailand. It appears in the trade from time to time, though not always identified correctly. It resembles H. orthogoniata and H. parclitella, but its saddle-shaped markings are more irregular, up to four in number, and often restricted to the upper half of the body.

Homalopteroides modestus is a small hillstream loach from the Salween, Mae Klong and Tenasserim rivers of southern Myanmar and western Thailand. Randall and Page (2012) redescribed it from Mae Klong specimens that had previously been identified as the congener H. smithi. A specialised micropredator of swift, clear, oxygen-saturated streams, it needs clean, well-oxygenated water and regular meals of live or frozen food.

Hypsibarbus vernayi is a cyprinid widespread in mainland Southeast Asia, from the Mekong basin in southern China to northern Peninsular Malaysia. Very similar to H. wetmorei, it has yellow pectoral, pelvic and anal fins (orange to red in H. wetmorei), so yellow-finned fish sold as H. wetmorei or 'lemon fin barb' appear likely to be this species. It prefers flowing water with abundant riparian vegetation and migrates seasonally.

Hypsibarbus wetmorei is a cyprinid widespread in mainland Southeast Asia, from the lower Mekong basin south to the Pahang River in Malaysia. Its orange to red pectoral, pelvic and anal fins separate it from the very similar H. vernayi (yellow), and yellow-finned fish traded as H. wetmorei or 'lemon fin barb' appear likely to be that species. It prefers flowing water with abundant riparian vegetation and grows to 250 mm.

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.

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.

The flying minnow, Laubuka caeruleostigmata, is a cyprinid from the Mekong system in Laos, Thailand and Cambodia, and the Chao Phraya and Mae Klong. Also known as 'leaping barb', it was once quite common in the ornamental trade and has apparently become scarce in the wild. It schools near the surface in main river channels, has a bright blue spot on top of the head, and is an accomplished jumper that needs a tightly-fitting cover.

Laubuka siamensis is a cyprinid from the Mekong, the Chao Phraya and Mae Klong in Thailand, and smaller drainages south to Peninsular Malaysia. Long considered synonymous with L. laubuca, it seems likely to be the species behind many of the fish entering the trade under that name. A conspicuous dark stripe, iridescent blue in life, runs uninterrupted along the rear of the body to an oval blotch on the caudal peduncle. It swims in groups at or just below the surface and is an accomplished jumper.

Lepidocephalichthys berdmorei is a cobitid loach found across Myanmar, Thailand, Laos, north-eastern India and Bangladesh. One of the most frequently-traded members of the genus, it is an excellent choice for those new to keeping loaches. Unlike most congeners it shows a preference for headwaters and streams with clear, flowing water, and its larger adult size separates it from the similar L. thermalis.

Lobocheilos melanotaenia is a grazing cyprinid from the Mekong in Laos, Thailand, Cambodia and Vietnam, plus the Dong Nai, Chao Phraya and Mae Klong. One of the most abundant species in the seasonal cyprinid migrations of the mainstream Mekong, it is available on a sporadic basis. It is told from L. rhabdoura by its deeper body, narrower mouth and a dark area in the dorsal-fin. It can be aggressive at feeding times and is not particularly tolerant of conspecifics.

Lobocheilos rhabdoura is a grazing cyprinid from Indochina, found in the Mekong, Chao Phraya and Mae Klong systems and south to Peninsular Malaysia. One of the most abundant species in the seasonal cyprinid migrations of the mainstream Mekong, it is available on a sporadic basis. It differs from L. melanotaenia in its shallower body, wider mouth and larger snout tubercules. It can be aggressive at feeding times and is not particularly tolerant of conspecifics.

Luciosoma bleekeri is a slender, pike-like cyprinid from the Mekong in Laos, Thailand, Cambodia and Vietnam, and from central and western Thailand. Subadults are traded regularly as 'apollo shark' or 'shark minnow' and it is frequently confused with L. setigerum, which has a series of black spots on the lateral line scales that this species lacks. It needs the largest private aquaria, and feeds mainly on terrestrial insects taken at the surface.

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.

Microdevario kubotai is a miniature cyprinid from peninsular Thailand and the Salween drainage in southern Myanmar. Relatively common in the ornamental trade, it is sold under names including 'green neon rasbora' and 'yellow neon rasbora'. It apparently inhabits calm to moderately-flowing, well-oxygenated headwaters and minor tributaries. In nature it typically occurs in groups of 20-50, and at least 8-10 are recommended.

Mystacoleucus greenwayi is a riverine cyprinid from the middle Mekong basin in Thailand and Laos and the Chao Phraya watershed. It favours clear, well-oxygenated running water over sand or gravel, often in rock and boulder-filled headwater streams. A schooling fish, it should be kept in a group of six or more alongside similarly-sized cyprinids, loaches and other riverine fishes, and like all Mystacoleucus it has a forward-pointing predorsal spine that can snag in a net.

Nemacheilus binotatus is a loach known only from the Mae Klong and Chao Phraya river systems of western and central Thailand. Its colour pattern is simply two dark stripes, one along the back and one from the snout through the eye along the flank, which separates it from N. longistriatus and N. ornatus. It lives in shallow, flowing stretches of streams over sand, gravel and leaf litter.

Nemacheilus masyae is a nemacheilid loach from Thailand and Peninsular Malaysia. Its flanks carry 14-18 short dark bars and its back 12-17 saddles. It occurs in both small blackwater forest streams and turbid main river channels. It is very similar to N. pallidus but has a more slender body, and its dark bars and saddles are wider than the light interspaces between them.

Nemacheilus pallidus is a nemacheilid loach from the Mae Klong, Chao Phraya and Mekong systems in Thailand, Laos, Cambodia and Vietnam. It inhabits streams and small rivers with clear to turbid water and substrates of mud, sand or small rocks. The similar-looking N. masyae is sometimes traded under this name, but N. pallidus has a deeper body and dark bars and saddles thinner than the light interspaces between them.

Opsarius koratensis is a cyprinid of the middle and lower Mekong in Thailand, Laos and Cambodia, and the Chao Phraya, Mae Klong and Dong Nai systems. It apparently inhabits larger, deeper and more turbid rivers than many congeners. Genetic evidence from Tang et al. (2010) suggests it may represent a distinct genus, and it occasionally appears in the ornamental trade.

Opsarius signicaudus is a cyprinid known only from headwater tributaries of the Mae Klong River in western Thailand. It inhabits well-oxygenated, moderate to fast-moving rivers and streams over gravel, cobbles and boulders, and is intolerant of organic wastes. A large, elongated blotch at the caudal-fin base helps separate it from congeners. It may have been exported for aquaria, though probably not under the correct name.

Paracanthocobitis zonalternans is a nemacheilid loach ranging from Manipur in India through Myanmar into western and peninsular Thailand. Several species are thought to be confused under the name, and Singer and Page (2015) consider it likely to be a species complex. Among the more peaceful members of the genus, it does best in a mixed-sex group of at least half a dozen, and it has been bred in aquaria, first by UK aquarist Mick Wright.

Pethia stoliczkana is a small cyprinid that appears to range from Manipur state in northeastern India through Myanmar and Thailand to western Laos. Much of the literature confuses it with P. ticto, but the two do not occur in the same waters and the lateral line is complete in this species and incomplete in P. ticto. The form from Mandalay division in Myanmar is sometimes sold as Puntius sp. 'pearlscale'. It mostly inhabits shady, flowing streams and tributaries.

Pseudohomaloptera sexmaculata is a hillstream loach from central and western Thailand, known only from the Chao Phraya and Mae Klong watersheds. An obligate dweller of swiftly-flowing streams and headwaters, it needs clean, well-oxygenated water. It closely resembles P. leonardi, and both are sometimes misidentified as P. yunnanensis. Members of the group mostly turn up as contaminants among shipments of other species and are usually sold as 'gecko' loaches.

Puntigrus partipentazona is a small cyprinid recorded from numerous river basins in Vietnam, Cambodia, Laos, Thailand and Peninsular Malaysia. It is easily told from congeners because the dark blotch on its dorsal fin extends onto the body. Typically found in heavily vegetated parts of rivers and sluggish streams, it is generally peaceful, though rival males continually battle for position within the group.

Schistura aurantiaca is a small nemacheilid loach known only from the Mae Khlong basin in Kanchanaburi Province, western Thailand. It is told apart from congeners solely by its colour pattern of 3-9 vertical orange bars on each flank. It inhabits riffles in clear, well-oxygenated headwater streams shaded by forest, and is possibly exported alongside similar-looking species such as S. cf. balteata.

Schistura geisleri is a small nemacheilid loach widespread in the Chao Phraya river system of western Thailand. It differs from most congeners in its small adult size, sociable behaviour and tendency to bury itself in the substrate when threatened. Peaceful with conspecifics, it is best kept in a group of four or more. It is available in the trade from time to time but is by no means common.

The chameleon loach, Syncrossus beauforti, is a botiid loach from Thailand and southern Myanmar, including the Chao Phraya and the Ataran River. It has been widely mislabelled as S. berdmorei in older aquarium literature, but has 9-10 branched dorsal-fin rays and rows of small dark markings across the body and head even when young. Adults reach 160-180 mm, and wild populations appear to have declined by at least 20-29% since 1997.

The banded tiger loach, Syncrossus helodes, is a botiid loach from the Mekong in Laos, Cambodia, Vietnam and Thailand, and the Chao Phraya. Reaching 250-300 mm, it lives in flowing waters from headwater streams to main channels and migrates into flooded areas in the wet season to feed and spawn. It is sometimes confused with S. hymenophysa but has small dark markings on the lower body, no dark spot in the dorsal fin and 10-12 bars without bluish borders.

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.

The sparkling gourami, Trichopsis pumila, is a small labyrinth fish from the lower Mekong basin and central and southern Thailand. Also known as the pygmy gourami, it has a solid dark midlateral stripe topped by a row of dark blotches, which with its small size separates it from T. schalleri. Both sexes produce audible 'croaking' sounds with a specialised pectoral mechanism, and most traded fish are produced commercially.

The croaking gourami, Trichopsis vittata, is a labyrinth fish found through much of Indochina, Peninsular Malaysia and Singapore. The largest of its genus, it produces audible sounds with a specialised pectoral mechanism unique within the Osphronemidae. Wild populations vary in colour pattern, and records from Borneo, Sumatra and Java might refer to a distinct species.

Trigonostigma somphongsi is a small rasbora, probably endemic to western Thailand and reckoned to occur somewhere in the Mae Klong basin. Exceptionally rare, it was considered potentially extinct for around a dozen years before a trio arrived in Germany among Boraras urophthalmoides in 2006. Its dark flank marking is reduced to a thickish black stripe, and captive stock is being bred to establish a sustainable population.

The silver loach, Yasuhikotakia lecontei, is a botiid loach from the middle and lower Mekong and the Chao Phraya and Mae Klong drainages of Thailand. Sometimes confused with Y. modesta, it is a slimmer, more elongate fish, usually brownish with a gold/green sheen, and its roundish caudal peduncle markings do not meet on the ventral surface. It forages under cover of dusk and darkness, and SF members report it milder in temperament than Y. eos and Y. morleti.

The redtail loach, Yasuhikotakia modesta, is a botiid loach from the middle and lower Mekong and the Chao Phraya and Mae Klong drainages of Thailand. One of the more commonly encountered botiids in the hobby, it is also sold as 'blue', 'orange-finned' or 'red-finned' botia. Some fish are dyed and sold as 'blueberry' or 'raspberry' loach, and their health is normally compromised by the process. Deeper-bodied than the similar Y. lecontei, it grows to 250 mm and needs an aquarium with a base of at least 150 ∗ 45 cm.

The skunk loach, Yasuhikotakia morleti, is a botiid loach from the middle and lower Mekong and the Chao Phraya and Mae Klong drainages of Thailand. Common in the hobby, where most fish are farmed commercially, it is also sold as 'skunk botia' or 'Hora's loach'. The dark stripe over its dorsal surface separates it from the similar Y. longidorsalis. It can be combative, nipping fins and harassing tankmates, especially when kept in smaller groups.

The bullseye snakehead, Channa marulius, is a large snakehead recorded from Pakistan across southern Asia to southern China, Laos and Vietnam. Also called the 'giant', 'cobra' or 'Indian' snakehead, it is widely accepted to represent a complex of related species in need of further research. Reports of 120-180 cm remain to be proven, with 500-600 mm a more common adult size, and it 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.

The clown featherback, Chitala ornata, is a large notopterid native to the Mae Klong, Chao Phraya and Mekong river systems of Thailand and Indochina. Also traded as the 'clown knifefish', it has rows of large ocellated spots above the anal-fin base and is regularly misidentified as C. chitala. It grows to 1000 mm SL and arguably has no place in the ornamental hobby, yet it remains popular, with albino and leucistic forms line-bred for the purpose.

Crossocheilus cobitis is a cyprinid ranging from the Mekong drainage in Laos, Vietnam and Thailand south to Sumatra, Borneo and Java. Primarily a lowland species, it lives in the turbid lower reaches of rivers over mud, close to submerged logs and similar objects. Given its wide range it has probably reached the trade as the invalid 'Crossocheilus siamensis', and it is likely to represent a group of similar-looking, closely related species.

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 Siamese tiger perch, Datnioides pulcher, is a large tiger perch from the Mae Klong, Chao Phraya, Mekong and Dong Nai river systems. Wild populations are hypothesised to have declined by more than 90% since the mid-1980s, and it has been locally extinct in Thailand since the 1990s. Highly sought after by aquarists, it usually has 4 broad dark bars, and D. microlepis is sometimes sold as D. pulcher to raise prices.

Garra fuliginosa is a cyprinid from the Mekong basin in Thailand, Laos, Vietnam and Cambodia, and the Chao Phraya and Mae Klong in Thailand. It tends to inhabit swiftly-flowing headwaters and tributaries with clear, oxygen-saturated water. Like other Garra it has a lower lip modified to form a mental adhesive disc for clinging to surfaces. The body is dark with random lighter scales.

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.

Hemibagrus spilopterus is a bagrid catfish from the Mekong and several other river systems in Laos, Vietnam, Cambodia and Thailand. Relatively common in the ornamental trade, it has been widely misidentified as H. nemurus, a Javan species that may never have been exported for aquaria. Given its size of up to 500 mm SL, its aggressive nature and a lifespan of several decades, it shouldn't be considered a home aquarium subject in all but the most exceptional circumstances.

The goldfin tinfoil barb, Hypsibarbus malcolmi, is a large cyprinid from Thailand, Laos, Cambodia and Peninsular Malaysia. It occurs throughout the Mekong system and in the Chao Phraya and Maeklong drainages, and in the Mekong migrates seasonally between larger river channels and flooded forests. Reaching 400 to 500 mm, it is suitable only for public aquaria or the very largest private set-ups.

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 red-finned cigar shark, Leptobarbus rubripinna, is a large pelagic cyprinid from the Mekong, Chao Phraya and Mae Klong river systems of Indochina. For decades it was referred to as its congener L. hoevenii, and both are still traded under the same name. A popular sport fish growing to 800 to 1000 mm, it is wholly unsuitable for private aquaria despite being readily available at 100 to 150 mm. It has a broad dark midlateral stripe and orange to red 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.

Amblyrhynchichthys micracanthus is a riverine cyprinid from the Mekong catchment in Laos, Thailand, Cambodia and Vietnam, and the Chao Phraya system. It moves into inundated forest during the wet season, and wild fish feed on periphyton, plankton and benthic algae. Older records of A. truncatus from mainland Indochina all refer to this species, which has a straighter snout profile, a shorter dorsal-fin spine and fewer gill rakers.

Gymnostomus lobatus is a cyprinid from the middle to lower Mekong basin in Laos, Thailand and Cambodia, and the Chao Phraya and Mae Klong in Thailand. It is considered one of the most abundant species in the massive seasonal migrations of cyprinids in the mainstream Mekong, and enters inundated forests in the wet season. The body is relatively slender and plain silver, with no dark marking on the caudal peduncle, and the snout often projects strongly.

The Siamese mud carp, Gymnostomus siamensis, is a cyprinid from the Mekong, Chao Phraya and Mae Klong basins in Laos, Thailand, Cambodia and Vietnam. Common in the Mekong main channel and larger tributaries, it moves into inundated zones to spawn in the wet season and is abundant in the massive seasonal migrations of cyprinids. It has a relatively deep, plain silver body and a large, broad head.

Mystacoleucus chilopterus is a pelagic cyprinid from the middle Mekong, Chao Phraya and Mae Klong basins in Laos and Thailand. It favours flowing lowland rivers and swiftly-flowing forest streams with rock and gravel. The anal fin has a concave margin and the dorsal and caudal fins black margins, and like all Mystacoleucus it has a forward-pointing predorsal spine that can become entangled in an aquarium net.

Nemacheilus troglocataractus is a blind cave loach known only from the Tham Sai Yok Noi cave system in Kanchanaburi Province, Thailand. Most specimens have no externally visible eyes and all are entirely depigmented. It is protected by Thai law and illegal to remove from its habitat, so the profile includes it for interest only.