Tonlé Sap

Barbodes aurotaeniatus is a small cyprinid from the middle and lower Mekong basin in Laos, Vietnam, Cambodia and Thailand. Uncommon in the aquarium trade, it has a single pair of maxillary barbels, lacking the rostral barbels of other Barbodes, and usually four small vertical black markings on the flanks. It inhabits streams, irrigation canals and ditches, and is apparently very peaceful, best kept in a mixed-sex group of 6 to 10.

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.

The Mekong bumblebee goby, Brachygobius mekongensis, is a tiny goby from the central and lower Mekong, including the Tonlé Sap system. It is apparently restricted to slow-moving or standing fresh water such as marshes, seasonal swamps and floodplains with dense aquatic vegetation. Narrow, often broken dark bars on a pale background separate it from the most similar species, B. nunus. It is poorly known in the hobby, and other species are sold under its name.

The redeye puffer, Carinotetraodon lorteti, is a small freshwater puffer from the lower Mekong basin and the Chao Phraya watershed in Indochina. It inhabits slow-moving to standing water in shady forest streams, minor tributaries and floodplains, often among dense vegetation. It tends to bite the fins of tankmates and is territorially aggressive, so is best kept alone, though a group can be kept with enough space and a suitable layout.

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.

Usually offered as the reticulated or fishnet flying fox, Crossocheilus reticulatus is a cyprinid from the Chao Phraya and Mekong basins. A silvery body, dark-edged scales and a dark caudal peduncle blotch set it apart from similar congeners. Patterning varies with collection locality, which led to several names now treated as synonyms. A fish of flowing streams, it is best kept in a group of six or more, since weaker individuals can be bullied in smaller numbers.

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 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.

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.

Epalzeorhynchos munense is a cyprinid from the Mun river and other tributaries of the middle Mekong in Thailand and Laos. It resembles E. bicolor and E. frenatum but has a black head, body and anal fin, red caudal and dorsal fins, and black margins on the pelvic and pectoral fins. A record from the Tonlé Sap system may refer to E. frenatum.

The Mekong flying barb, Esomus longimanus, is a cyprinid from the Mekong basin in Thailand, Laos, Cambodia and Vietnam, and the Tonlé Sap system. It favours shallow, slow-moving and standing waters with dense aquatic vegetation, such as ditches, marshes and rice paddies. Like other Esomus it has greatly enlarged pectoral fins and very long maxillary barbels, and it jumps well enough to escape through the tiniest gaps.

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.

Garra fasciacauda is a cyprinid native to the Mekong river system in Thailand, Laos, Vietnam and Cambodia, including the Tonlé Sap basin. It has a black submarginal stripe on both caudal lobes and a plain dorsal fin. It inhabits swiftly-flowing water and migrates seasonally, with many fish moving from the Tonlé Sap system to the Khone Falls in the dry season.

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.

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.

Kryptopterus geminus is a silurid catfish from the lower and middle Mekong in Thailand, Laos, Cambodia and Vietnam, and the lower Chao Phraya. Wild populations were formerly considered K. cryptopterus, and it is likely to be traded as that very similar species. It differs in having a narrower head, a longer snout and anal fin and more laterally-placed eyes, and inhabits flowing rivers and larger streams with turbid water.

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 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.

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.

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.

Traded as 'butterfly barb' or 'mackerel barb', Opsarius pulchellus is a cyprinid from the Chao Phraya and mid-to-lower Mekong basins. It occurs in Thailand, Laos, Cambodia and Vietnam, typically in submontane headwaters and fast-flowing minor rivers and streams. Also sold as 'royal opsarius', it carries 7-10 elongate vertical bars on each flank, and like its congeners is too fast and vigorous a feeder for the general community.

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.

Trichopsis schalleri is a croaking gourami from the lower Mekong basin and the Chao Phraya watershed in Thailand, Laos, Cambodia and Vietnam. Sometimes called the Mekong croaking gourami or three-stripe gourami, it is larger than the similar T. pumila, and its upper body stripe varies with mood and sometimes fades entirely. Peaceful unless breeding, it can be kept in a pair or a group.

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 royal featherback, Chitala blanci, is a very large notopterid endemic to the Mekong drainage in Laos, Thailand, Vietnam and Cambodia. Also sold as the 'royal knifefish', it reaches 1200 mm SL and arguably has no place in the ornamental hobby, being suitable only for public installations or the very largest private aquaria. Many small dark spots on the front of the body merge into oblique stripes, and it is thought to be threatened by dam construction.

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.

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

The Asian red tailed catfish, Hemibagrus wyckioides, is a bagrid from the Mekong system in China, Laos, Vietnam, Cambodia and Thailand. It also occurs in the Chao Phraya drainage. The largest bagrid in central Indochina, it reaches at least 900–1000 mm and 70–80 kg, and the largest specimen known measured 1300 mm. Juveniles are sometimes sold, but buying them is strongly discouraged given its size, aggression and a lifespan of several decades.

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 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.

Gymnostomus ornatapinnis is a small cyprinid known only from the Mekong River system in Laos, Thailand and Cambodia. It appears to favour still or slow-moving, often temporarily-inundated, marginal habitats away from the major river channels. Barbels are completely absent, the caudal peduncle is very deep, and the pectoral, pelvic and anal fins are usually reddish-orange or rose-tinted.

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.

Labeo pierrei is a large cyprinid from the Mekong river system in southern China, Laos, Thailand, Cambodia and Vietnam, and the Dong Nai in Vietnam. It grows to 800 mm and inhabits main river channels and large, deep tributaries. It migrates seasonally, moving upstream into the Sekong, Sesan and Srepok rivers at the onset of the wet season and returning downstream in the dry months.