India

The red-tailed squirrel loach, Aborichthys elongatus, is a nemacheilid loach from Darjeeling District, West Bengal, in north-east India. It lives among rocks and cobbles in shallow, swift streams running down from the Sivalik Hills into the Teesta and Brahmaputra drainage. The species is quite rare in the trade, and most fish sold under the name are collected at lower altitudes in Jalpaiguri District and probably represent different species.

Aborichthys sp. 'AR01' is a nemacheilid loach, apparently undescribed, known only from the Raidak I River basin in West Bengal, India. It is usually traded as A. elongatus, but that species appears endemic to higher-altitude waters in Darjeeling District, and the colour and patterning of the two are clearly different. It inhabits shallow, swiftly-flowing water over gravel and small rocks.

Aborichthys sp. 'AR02' is a small nemacheilid loach, apparently undescribed, known only from the Raidak I River basin in West Bengal, India. It occasionally turns up as a contaminant in shipments of A. sp. 'AR01'. Its small adult size, which seems to be 30 to 35 mm SL, and its relatively wide dark vertical bars along the body and single reddish bar in the caudal fin set it apart from others in the genus.

The peacock loach, Acanthocobitis pavonacea, is a large nemacheilid loach from the Brahmaputra River drainage in Assam, northeastern India. At 120 to 156 mm SL it is one of the largest nemacheilids, and Singer and Page (2015) treat it as the only member of Acanthocobitis. It isn't common in the trade, but occasional specimens turn up among wild-caught shipments from northeast India, sometimes sold as 'panther' or 'puma' loach.

The half-banded loach, Acoura savona, is a nemacheilid loach from Ganges tributaries draining the eastern Himalayas in India, Nepal and Bangladesh. The species is seen in the trade fairly often and is sometimes sold as 'bicolor loach' in the United States. Its colour pattern of 9-10 thin, yellowish bars on a dark upper body, with plain whitish lower parts, separates it from similar loaches, and it is among the less aggressive of them.

The Indawgyi stream catfish, Akysis prashadi, is an akysid catfish from Lake Indawgyi and the upper Ayeyarwady drainage in northern Myanmar. It has also been recorded from the Lokchao river in Manipur, India. At up to 62 mm SL it ranks among the largest in the genus, and though it has been exported for the hobby it is by no means common.

The green panchax, Aplocheilus blockii, is a small killifish from Sri Lanka and southern India, growing to around 45 mm SL. Euryhaline, it mostly inhabits lowland, often coastal, still or slow-moving brackish or fresh water with surface vegetation or overhanging cover, and is commonly found in mangrove swamps and rice paddies.

The striped panchax, Aplocheilus lineatus, is a predatory killifish from peninsular India and northern Sri Lanka, growing to 10 cm TL. It lives in permanent water from mountain streams and lakes to swamps and rice paddies, and is not an annual species. The golden wonder panchax sold in the trade is a golden form selectively bred in the hobby that does not occur in the wild.

The dwarf panchax, Aplocheilus parvus, is a small killifish from Sri Lanka and Tamil Nadu state, southeastern India, growing to around 40 mm SL. Euryhaline, it mostly inhabits lowland, often coastal, still or slow-moving brackish or fresh water, and is commonly found in mangrove swamps and rice paddies.

Badis assamensis is a badid from the Brahmaputra River basin in Assam state, northeast India, and the largest species in its genus. Like most badids it is poorly documented. Its body patterning is almost identical to that of B. blosyrus, but it grows slightly larger, to 65 to 75 mm, and has a noticeably shorter jaw profile. The neotype was collected from a slow-moving forest stream in the Dibru River drainage, and it is a slow-moving, retiring fish that more boisterous tankmates can outcompete for food.

The badis, Badis badis, is a small badid from the Ganges river system in India, Nepal and Bangladesh, with further records in Assam and the Mahanadi. Sometimes sold as the 'chameleon fish' for its ability to change colour rapidly, especially when breeding or stressed, it was one of only two badids popular in the hobby before 2002. Several congeners share its dark cleithral spot and can be hard to tell apart. It is sluggish and retiring, and rival males can be quite aggressive towards one another in confined spaces.

Badis blosyrus is a badid from western Assam and northern West Bengal in India, in the Brahmaputra drainage. Like most badids it is poorly documented. Its body patterning is almost identical to that of B. assamensis, but it is slightly smaller and has a noticeably elongated, better-developed jaw. In the Raidak River it was collected from cool, shallow, flowing water over small rocks and sand, with thick marginal vegetation.

Badis sp. 'Buxar' is an undescribed badid from India, named after the Buxa (often spelled 'Buxar') National Park in West Bengal. It has been in the hobby since 2006 and is also sold as B. sp. 'flame dot', after the red centres to the body scales of males. It appears to belong to the B. corycaeus group. Rival males can be very aggressive towards one another, especially in smaller tanks.

Badis tuivaiei is a badid from northeastern India, described from the Tuivai and Irang rivers in the Barak system of Manipur state. It has since been found in the Wahumiam River in Meghalaya, where fish collected in 2006 were first thought to be undescribed and called B. sp. 'Wahumiam River' or 'terracotta'. It is very similar to B. badis, B. chittagongis and B. kanabos and is separated from them by meristic counts. At the Wahumiam locality the water was clear, shallow and slow over boulders, pebbles and sand.

Barilius vagra is a cyprinid widely distributed in the Ganges and Brahmaputra river systems of northern India, Nepal and Bangladesh. Poorly known in the hobby but exported on occasion, it has 10 to 14 vertical bars on each flank that do not extend below the lateral line. It inhabits well-oxygenated, fast-flowing rivers and tributaries with gravel, cobble and boulder substrates, and its speed and vigorous feeding make it unsuitable for the general community.

The Malabar batasio, Batasio travancoria, is a bagrid catfish endemic to southern Kerala, India, in the Pamba, Chittar and Kallada drainages. Its darkish midlateral stripe and poorly-defined post-opercular spot separate it from B. sharavtiensis, the only other described member of the genus in southwestern India. Like its congeners it is an obligate inhabitant of shallow, fast-flowing, highly-oxygenated headwater streams.

Betadevario ramachandrani is a danionin cyprinid known only from two sites in the upper Sita River drainage near Agumbe, Karnataka, India. Agumbe lies in heavily forested country in the Western Ghats and is among the rainiest places in India. An active species, it suits a tank set up like a flowing stream at 18 to 23 °C, and its constant movement and vigorous feeding can stress less active tankmates.

Bhavania australis is a balitorid loach endemic to the Western Ghats mountains of southern India, recorded from Kerala, Tamil Nadu and Karnataka. An obligate dweller of shallow, fast-flowing, highly-oxygenated headwaters and minor tributaries, it has a flattened head and body and horizontally extended paired fins that form a powerful sucking cup for clinging to rocks. It is very rarely seen in the international aquarium trade but is maintained by a number of Indian aquarists.

The yo-yo loach, Botia almorhae, is a botiid loach from parts of the Ganges River drainage in northern India and possibly Nepal. It is often called the 'Pakistani' loach, but that name is a misnomer. B. almorhae sensu stricto appears to belong to a group of closely-related species and has possibly never been seen in the aquarium trade, where the most commonly available members seem to be B. lohachata, B. sp. 'Kosi' and B. sp. 'Teesta', plus assorted hybrids.

The Bengal loach, Botia dario, is a botiid loach from the middle to lower Ganges and Brahmaputra drainages in northern India, Bangladesh and Bhutan. Its yellow to golden body carries 7-9 dark bars with thinner, lighter bars between, and its particularly curved head makes it among the most easily recognisable in the genus. Botia macrolineata, described from aquarium fish shipped via Bombay, represents the same species. It is among the botiids produced commercially using hormones.

Known in the trade as the 'Burmese loach', Botia histrionica is a botiid loach from Myanmar, Manipur in India and Yunnan, China. Young fish all carry five solid dark bars on each flank and are often confused with B. kubotai, but in B. histrionica the bars stay solid for longer and the central bar usually forms a 'y' shape. Adult patterning varies considerably between the Ayeyarwady, Salween, Manipur and Ataran forms, and there has been speculation that some represent distinct species.

Botia rostrata is a botiid loach from the lower Ganges and middle to lower Brahmaputra basins in northern India and Bangladesh. Traded as the 'Gangetic loach', 'twin-banded loach' or 'ladder loach', almost all fish sold under the name are B. sp. 'upper Brahmaputra', and B. rostrata sensu stricto is rarely, if ever, available. Juveniles carry 9-10 dark body bars, usually in pairs, which break up to differing extents as the fish grow.

The zebra loach, Botia striata, is a botiid loach from the Krishna River system in southern India, described from the Tunga River in Karnataka. Its yellow to golden body with blue, green, grey or black bars and typically red mouthparts make it one of the most easily recognised in the genus, although the bars break up entirely in some specimens. Given its adult size and peaceable nature it is perhaps the best choice of Botia for the general community.

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 crazy fish, Butis butis, is a flathead gudgeon of coastal and brackish waters across the Indo-Pacific, from eastern Africa to Fiji. The most commonly traded member of the genus, it has many other names, including crocodile fish, duckbill sleeper and upside-down sleeper. A nocturnal ambush predator, it often swims upside-down, and it is territorial and not sociable with conspecifics, so is best kept singly.

The moose-faced loach, Canthophrys gongota, is a cobitid loach from the Ganges and Brahmaputra river systems in Nepal, northern India and Bangladesh. Often referred to as Somileptes gongota in aquarium literature, it is rarely seen in the trade, being notoriously delicate and difficult to ship. It mostly inhabits slow-moving, shallow tributaries and minor rivers over mud, sand or gravel.

Chagunius chagunio is a large cyprinid endemic to the Ganges and Brahmaputra river basins in northern India, Nepal and Bangladesh. Growing to 400-450 mm, it can only be considered suitable for public aquaria and a very small minority of private aquarists. Rarely seen in the trade, it looks almost identical to C. baileyi and C. nicholsi but has more circumferential and circumpeduncular scales.

The Indian glass fish, Chanda ranga, is a small ambassid from South and Southeast Asia, with translucent skin that shows its bones and organs. For many years it was injected with luminous dyes on Asian fish farms and sold as 'painted' glass fish, and most injected fish do not survive more than a few months. It is found most often in freshwater, frequently soft and acidic, and needs no added salt. Parambassis lala and C. siamensis are often imported under its name.

Traded for years as 'Lal Cheng', Channa andrao is a snakehead endemic to the Brahmaputra River basin in northeastern India. It stays at a manageable size while showing much of the behaviour and colour of larger members of the genus. It lacks pelvic fins and is most often confused with C. bleheri, from which it differs in fin markings and in being a paternal mouthbrooder.

The orange-spotted snakehead, Channa aurantimaculata, is a snakehead endemic to the Brahmaputra basin in Assam and Arunachal Pradesh, India. Also traded as 'golden cobra snakehead', it has seven or eight large, irregular orange blotches on a dark upper body. Aggressively territorial towards its own kind, it needs a species tank, and violence can break out suddenly even in pairs kept together for a long time.

The rainbow snakehead, Channa bleheri, is a snakehead endemic to the Brahmaputra basin in Assam and Arunachal Pradesh, northeastern India. A popular aquarium fish, it lacks pelvic fins and has reddish orange markings on the caudal fin. Both parents guard the floating eggs. It has been recommended as a concern for conservation because of its restricted range and burrow habitat, though it is unclear whether collection for the trade affects wild populations.

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 Assamese snakehead, Channa stewartii, is a snakehead of the C. gachua group from the Brahmaputra and Ganges basins of India, Bangladesh and Nepal. It is also listed from Bhutan and Myanmar and grows to about 30 cm TL. Keepers give it a cooler winter of about 16-18 °C, it is aggressive towards its own kind, and the male broods the eggs in his mouth.

The neon hatchet fish, Chela cachius, is a deep-bodied cyprinid mostly recorded from the Ganges and Brahmaputra systems of India and Bangladesh. Its extremely deep body means it is unlikely to be confused with any related species, and it is the only valid member of the genus. A habitat generalist, it is an active schooling fish that is best kept in a group of at least 8-10 in a tank with a tightly-fitting cover, since it is an accomplished jumper.

The frail gourami, Ctenops nobilis, is an anabantoid from the Ganges and Brahmaputra systems in northeastern India, Bangladesh and Nepal. The only recognised member of its genus and a paternal mouthbrooder, it is usually regarded as very difficult to keep but is quite adaptable once acclimatised. It appears to react poorly to export and shipping, so imports are often in poor condition and prone to Oödinium. Adults can be openly hostile towards conspecifics.

The moustached danio, Danio dangila, is a cyprinid from the Ganges and Brahmaputra drainages, with most records from Nepal, India and Bangladesh. The common name refers to its exceptionally long barbels, and despite its apparent abundance in nature it remains uncommon in the hobby. Its constant activity can upset slow-moving or timid tankmates, so it suits larger tanks with similarly-sized fishes, and adult size appears to vary by population from 60 to 130 mm.

Danio jaintianensis is a small cyprinid known only from the Jaintia Hills of Meghalaya, in the Brahmaputra system of northeastern India. It is likely to be restricted to small, slower-moving hill streams with gravel and rocky substrates and thick marginal vegetation. It is best kept in an unheated tank and tends to struggle above 25 °C for long periods. Its temperature needs and rarity make it hard to recommend for the general community.

Much of Meghalaya consists of forested hills which receive a great deal of rainfall and many of its waters flow swiftly. This species typically inhabits high elevation (> 1000 m amsl) streams running over rocky, boulder-strewn substrates with few aquatic plants, although at some localities the flow may be more sluggish with riparian vegetation providing shade.

The zebra danio, Danio rerio, is a small cyprinid from India and Bangladesh, found mostly in slow or still pools and mature rice paddies. Peaceful, hardy and inexpensive, it has been mass-produced for many years and quality stock can be hard to find. The spotted 'leopard danio' is a spontaneous mutation of the striped form that also occurs in the wild.

Danionella priapus is a miniature cyprinid known only from the Jorai River, a Sankosh tributary in the Brahmaputra drainage of West Bengal, India. Males have a conical projection of the genital papilla forming a funnel between the pelvic fins, a feature that may be unique within the Cypriniformes. Referred to as D. sp. 'Jorai River' before its description, it grows to 16 mm SL and was collected from a sluggish, densely vegetated stream alongside Dario dario.

The scarlet badis, Dario dario, is a tiny badid from tributaries of the Brahmaputra in West Bengal and Assam, India. Among the smallest percoid fishes known, it grows to 20 mm SL and is a popular choice for 'nano' aquaria. Males are the only Dario with seven iridescent blue vertical bars on the flanks, and rival males can be very aggressive towards one another in confined spaces.

Dario kajal is a tiny badid from the Meghna drainage, described from the Jaintia Hills of Meghalaya, India, and also found in Bangladesh. It was referred to as Dario sp. 'Jaintia Hills' or D. sp. 'Bangladesh' before its description, and its name alludes to its prominent orbital stripes. Males have bars arranged in pairs on the upper half of the body, and given its rarity it is best kept alone with the emphasis on captive reproduction.

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.

Dawkinsia arulius is a cyprinid from Karnataka, southwestern India, apparently now restricted to the upper Cauvery and the Tungabhadra headwaters. Adults have three large, diffuse dark markings on the body. It appears extirpated at its type locality, most likely because of the Krishna Raja Sagara dam upstream, and the fish traded as 'arulius barb' is often the related D. tambraparniei, in which males have filamentous dorsal-fin rays.

The mascara barb, Dawkinsia assimilis, is a cyprinid from the Netravati, Chalakudy and Kallada basins of Karnataka and Kerala, India. The caudal-fin lobes are tipped with a black band about as wide as the eye, faint or absent in Kallada fish. Misidentified in the past as Puntius mahecola, it still appears on trade lists as 'mahecola barb', and some populations might represent distinct species.

Dawkinsia chalakkudiensis is a cyprinid from Kerala, southern India, known from the Chalakudy, Periyar, Pamba and Achankovil rivers. It was first exported in 1996 as D. denisonii, from which it differs in its inferior mouth, a black marking in the dorsal fin, and a duller scarlet body stripe. It can be belligerent and is unsuitable for the general community aquarium.

The red-line torpedo barb, Dawkinsia denisonii, is a cyprinid endemic to Kerala and Karnataka in southern India. It is still often sold as Sahyadria denisonii. Extremely popular since it appeared in the trade in the late 1990s, it is listed as Endangered by the IUCN, and collection for the aquarium trade has been held largely responsible for its decline. Large numbers are produced in Southeast Asia and Eastern Europe. The similar D. chalakkudiensis is occasionally traded as this species and is more belligerent.

Dawkinsia exclamatio is a cyprinid from the Kallada River in southern Kerala, India, and may be endemic to that river system. Rare in the hobby, it occasionally arrives as bycatch among similar-looking species such as D. assimilis. Two black blotches on each flank set it apart from the rest of the group, but there is a case that it is a natural hybrid between D. assimilis and a D. arulius-like fish found with it at its type locality.

The filament barb, Dawkinsia filamentosa, is a cyprinid endemic to the Western Ghats region of southern India, in Kerala, Tamil Nadu and Karnataka. Adult males and some females develop filament-like extensions to the branched dorsal-fin rays. Most common in lowland coastal floodplains, it occurs in fresh and brackish water, and it also appears on trade lists as 'blackspot barb' or 'mahecola barb'.

Dawkinsia rohani is a cyprinid known only from Kanyakumari District, Tamil Nadu state, at the southern tip of the Indian peninsula. A single black club-shaped blotch running back to the caudal-fin base, with no other body markings in front of it, separates it from congeners. Habitat data are lacking, but it is a pelagic, riverine species and apparently most common in hill streams.

Dawkinsia rubrotincta is a cyprinid from southern India, considered widespread throughout the Cauvery drainage in Karnataka, Kerala and Tamil Nadu. It may have appeared in the trade under the misapplied names Puntius arulius and P. tambraparniei. Three small, well-defined dark body markings separate it from D. arulius, D. srilankensis and D. tambraparniei, in which the markings are larger and more diffuse.

The 'arulius' barb, Dawkinsia tambraparniei, is a cyprinid possibly restricted to the middle Tambraparni River basin in Tamil Nadu, southern India. Described as a subspecies of D. arulius, it appears in most earlier aquarium literature as Puntius arulius or 'arulius barb' and is often still traded as such, although D. arulius is quite different-looking and rarely exported. Many fish in the trade are likely to have been bred commercially.

Devario acuticephalus is a small devario from Manipur state in northeastern India, also known from neighbouring Nagaland. It is rare in the hobby but traded on occasion. D. apogon from Yunnan, China, is very similar but has dark vertical bars on the front of the flanks. During a 2010 IUCN assessment it was recorded from only a handful of localities, and it is likely restricted to small hill streams.

Devario aequipinnatus is a striped devario from hill streams in northeastern India, Bangladesh and Nepal. It is recognised by three straight dark stripes along each side, of which the middle one is widest. The name was long applied to almost any striped Devario, including the commercially bred giant danio, which is covered here under D. malabaricus.

Devario assamensis is a deep-bodied devario from Assam and West Bengal in northeastern India, in tributaries of the lower Brahmaputra. It has been traded as Devario sp. 'Mirik red', D. sp. 'redline' and D. sp. 'blood stripe', but is very rare in the hobby. If the distribution records are correct, it occurs from around 250 m AMSL in Darrang to 1767 m at Mirik, and possibly higher in Bhutan.

The Bengal danio, Devario devario, is a devario from the Ganges and Brahmaputra river systems in northern India, Nepal and Bangladesh. Also known as the 'Sind danio', it is told apart from congeners by a single, interrupted lateral stripe on each flank. It is relatively common in the trade and produced commercially, with an albino form and a short-bodied variant sometimes sold as D. sp. 'mini Putao'.

The giant 'danio', Devario malabaricus, is a deep-bodied devario from peninsular India, living in hill streams and upper parts of small rivers. Most older aquarium literature labels it D. aequipinnatus, but genetic and morphological data have shown the traded fish to be D. malabaricus. It has a blue-and-yellow colour pattern and a P stripe extending to the fork of the caudal-fin. Its true range is uncertain and may be confined to western-flowing drainages of India.

The peninsular 'danio', Devario neilgherriensis, appears endemic to tributaries of the Bhavani river system in the Nilgiri Hills, southern India. It is almost unheard of in the trade and little is known about it. Day described it with silvery flanks and a broad, indistinct steel-blue stripe bounded above and below by a narrow bright yellow band. Several of its hill-stream habitats lie around 2000 m AMSL.

The green puffer, Dichotomyctere fluviatilis, is a widespread puffer from South and Southeast Asia, found in slow-moving rivers and estuaries. It is often confused with D. nigroviridis and Tetraodon schoutedeni but has a more slender, streamlined shape. Though often sold in freshwater, it is a true brackish species and needs a specific gravity of around 1.005 to 1.010 to survive long term. It is still often sold as Tetraodon fluviatilis.

The flying barb, Esomus danrica, is a cyprinid with an enormous range across Pakistan, Nepal, Bangladesh, most of India, Myanmar and Sri Lanka. It shows a marked preference for shallow, slow-moving and standing waters such as rice paddies with dense vegetation, and is generally absent from major river channels. Reports on its suitability for community aquaria are mixed, with some keepers seeing a pronounced tendency to nip fins.

The Canara pearlspot cichlid, Etroplus canarensis, appears to be endemic to the Kumaradhara-Netravati river system in southern Karnataka, India. Also known as the banded chromide or 'roman numeral' cichlid, it lives only in oxygen-rich fresh water, unlike its euryhaline relatives. Unmanaged collection raised concerns over its status, and commercial breeding in Southeast Asia has since reduced the pressure on wild stocks. Sexual maturity takes around 24 months.

The rhino garra, Garra bicornuta, is a cyprinid from the Tunga River in the upper Krishna drainage, Karnataka, southern India. No other Garra is known to have a pair of rostral processes, which males develop and hold erect when sparring. A blue opercular spot ringed with gold blotches also identifies it. It is traded as 'Tunga garra' or 'lionhead garra', and can be territorial, especially at feeding time.

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 melon barb, Haludaria fasciata, is a small cyprinid endemic to the Western Ghats of southern India, in Goa, Karnataka, Kerala and Tamil Nadu. It exists in a number of colour forms, and it is undecided whether they are geographical variants or a complex of closely-related species. Also traded as the 'ember barb', 'banded barb' and 'black spot barb', it is relatively peaceful and hardy, but a vigorous feeder that may outcompete slower or more timid fishes.

The Asian stone catfish, Hara jerdoni, is a tiny sisorid catfish from India and Bangladesh, found in slow-moving streams and small rivers. It grows to around 30 mm SL and is told apart from others in the genus by its elongated pectoral spines. It and its congeners also go by the name moth catfish, after their patterning and shape when viewed from above. Very peaceful, it prefers soft substrates and is outcompeted by active bottom-dwelling species.

The liver catfish, Heteropneustes fossilis, is a catfish from Iran, Pakistan, India, Nepal, Sri Lanka, Bangladesh, Myanmar and the Andaman Islands. Also known as the stinging or fossil catfish, it carries venom sacs at the base of the pectoral spines and its sting is very painful, so it is not recommended for the inexperienced. Exceptionally hardy and long-lived, it can breathe atmospheric air to a certain extent and survives in sluggish, oxygen-deficient swamps and ditches.

The black collared catfish, Horabagrus nigricollaris, is a bagrid catfish endemic to the Chalakudy River in Kerala, south-western India. The rarer of the two species in the genus in the hobby, it resembles the much larger H. brachysoma. Both are usually sold as juveniles, and in this species the black shoulder marking extends up and over the top of the body, giving the collar that names it.

Jerdon's carp, Hypselobarbus jerdoni, is a large cyprinid endemic to India, recorded from Maharashtra, Karnataka, Kerala and Tamil Nadu. A riverine fish of clear, well-oxygenated, running water, it can reach 46 cm and is very rarely encountered in the trade. Very active and a vigorous feeder, it needs a tank of 240 ∗ 120 ∗ 120 cm or more for a group of adults, and many Indian authors consider it endangered.

The violet shark, Labeo boga, is a cyprinid from most major river systems in India, Pakistan, Nepal, Bangladesh and Myanmar. It inhabits major river channels and larger tributaries and grows to 250 mm, needing a tank of at least 240 x 60 cm. It is unsuitable for most home aquaria but turns up in the trade irregularly, also as the 'violet-gilled shark' or 'blushing violet shark'. L. boga as currently recognised probably represents a complex of closely-related species.

The Malabar hatchet chela, Laubuka fasciata, is a cyprinid endemic to the state of Kerala in southwestern India. A dark stripe runs from the eye to the caudal peduncle, and it favours slow-moving, shallow margins of rivers and streams over rock and gravel. It is occasionally available in the aquarium trade, apparently collected only in small numbers, and is an accomplished jumper.

The Indian glass barb, Laubuka laubuca, is a cyprinid probably endemic to the Ganges-Brahmaputra system in northern India, Bangladesh and Nepal. Traditionally considered to occur across the Indian subcontinent and most of Southeast Asia, it appears to be far more restricted, and many fish in the trade are probably L. siamensis. L. laubuca has a roundish, ocellated humeral spot and a thin, less conspicuous stripe interrupted by vertical markings. Other names include 'Indian hatchet fish' and 'winged danio'.

Lepidocephalichthys annandalei is a cobitid loach from the mid-to-lower Ganges and Brahmaputra systems in Nepal, Bangladesh and north-east India. Rarely traded, it has been sold as L. sp. 'peacock', presumably for its caudal-fin pattern of two dark v-shaped markings, unique within the genus. Fish in the trade differ slightly from the original description, in particular lacking a notched caudal fin.

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.

Lepidocephalichthys goalparensis is a cobitid loach from the Brahmaputra, Ganges and upper Irrawaddy basins in India, Nepal, Bangladesh and Myanmar. Rarely seen in the hobby, it was imported into the UK in late 2011 as bycatch among mastacembelid eels from northern India, and the identification was confirmed by Justin Havird. The forked caudal fin normally carries four or five broad, dark V-shaped bars.

Lepidocephalichthys guntea is a cobitid loach from the Ganges and Brahmaputra systems of northern India, Nepal and Bangladesh, and much of Myanmar. One of the most frequently-traded members of the group, it is an excellent choice for those new to keeping loaches. Males carry a solid, dark lateral stripe and females spotted flanks, and patterning varies with origin. It is also used as a food fish, eaten fresh and dried.

Lepidocephalichthys micropogon is a cobitid loach from Myanmar, western Thailand, Bangladesh and Assam, India. Known from the Salween, Sittaung, Irrawaddy and Brahmaputra drainages and occasionally exported as bycatch, it grows to 55 mm SL and has a strongly forked caudal fin with broad, dark V-shaped bars. Kottelat (2012) treats L. manipurensis as a synonym, though Havird and Page (2010) list the two separately.

Lepidocephalichthys sp. 'LE2' is a cobitid loach from northern West Bengal, India, and most likely an undescribed species. It was apparently collected in the Buxa Tiger Reserve alongside the dwarf snakehead traded as Channa sp. 'Assam' or 'Lal Cheng'. It shows characters of both L. alkaia and L. guntea, has been referred to as L. cf. guntea, and the specimens pictured reached the UK in 2007.

Lepidocephalichthys thermalis is a cobitid loach from Sri Lanka and Peninsular India, described from the hot waters of Cania, Sri Lanka. Available sporadically, it makes an excellent choice for those new to keeping loaches. Unlike most of the genus it shows a preference for headwaters and clear, flowing streams. It was for a number of years included in Lepidocephalus until Havird and Page (2010) placed it in Lepidocephalichthys.

The tyre-track eel, Mastacembelus armatus, is a spiny eel from South Asia and Myanmar, also known as the white-spotted spiny eel. Growing to around 91 cm, it hides during the day and often buries itself, so it needs sand, plenty of hiding places and a close-fitting hood. It eats live fish in the wild, and tankmates should be too large to be considered prey.

Mesonoemacheilus guentheri is a loach from the Western Ghats of southern India, described from the Nilgiri Hills and since recorded in Kerala. Outside India it is most often seen as bycatch among shipments of M. triangularis. It is often confused with M. herrei, since both have rows of yellowish, dark-edged spots, but its spots are rounded where those of M. herrei are 'Y' or 'V' shaped. Some aquarists report it as peaceful and others as territorial and aggressive.

Mesonoemacheilus herrei is a loach from the Anaimalai Hills of the Western Ghats in Tamil Nadu, southern India. It is unclear if it has ever been exported outside India, though the odd specimen may turn up among shipments of M. guentheri or M. triangularis. It was earlier considered synonymous with M. guentheri and shares its rows of yellowish, dark-edged spots, which in this species are 'Y' or 'V' shaped.

Mesonoemacheilus petrubanarescui is a loach from the Netravati and Kabini river basins in the Western Ghats of southern India. It may be endemic to these two drainages. The dorsal surface carries 7-8 dark, saddle-shaped markings and the flanks a varying number of broken bars. It is unclear if it has been traded outside India, but it may turn up among shipments of M. guentheri or M. triangularis.

The zodiac loach, Mesonoemacheilus triangularis, is a loach from the Western Ghats of Kerala and Tamil Nadu in southern India. Also called the 'Batik loach', it is relatively common in the aquarium trade. Pale, black-edged saddles along the back and a similar set of bars from the belly set it apart from its congeners. Aquarists differ on its temperament, some finding it peaceful and others territorial and aggressive.

The swamp eel, Monopterus albus, is very widespread, found from India and China to Japan, Indonesia, the Philippines and Australia. Not a true eel, it has a single gill slit and an accessory breathing organ, and during dry spells it burrows into wet earth. Growing to around 100 cm, nocturnal and piscivorous, it is best kept singly, and the tank must have an extremely tightly-fitting, heavy cover.

Day's mystus, Mystus bleekeri, is a bagrid catfish from India, Pakistan, Nepal, Bangladesh, Bhutan, Myanmar and Indonesia. It superficially resembles the more common M. vittatus but grows larger, to around 155 mm, and has a much longer adipose fin. Peaceful and gregarious, it suits communities of larger fish, though adults will probably eat small fish, and it is more outgoing in a small group.

Nemacheilus anguilla is a loach endemic to the Western Ghats of southwestern India, recorded from rivers in Maharashtra, Karnataka and Kerala. Dark flank markings merged into a lateral stripe separate it from other Indian congeners, and its generic placement requires further study. It inhabits well-oxygenated, moderate to fast-flowing rivers over gravel and boulders, and is peaceful with its own kind, best kept in a group of four or more.

Nemacheilus corica is a loach from Himalayan foothill rivers of the Ganges and Brahmaputra systems in Nepal, northern India and Bangladesh. Usually referred to Schistura in the hobby, it has been placed in Nemacheilus by most authors since the late 1970s, though its generic placement requires further study. A row of variably sized dark spots runs along the back and another along each flank, both ending in a dark blotch at the caudal-fin base.

Nemachilichthys rueppelli is a nemacheilid loach from the upper Krishna River system in the Western Ghats, India. It inhabits moderate to fast-flowing streams and rivers, usually on the bed among aquatic vegetation and submerged roots. N. shimogensis was long treated as a separate species, but Keskar et al. (2015) examined topotypes of both and concluded they are conspecific.

The dadio, Laubuka dadiburjori, is a small cyprinid endemic to southern India, recorded from Goa, Karnataka, Kerala and Tamil Nadu. It has also been marketed as 'Burjor's brilliance', 'orange chela' and 'orange hatchetfish', and does not exceed 30 mm SL. A dark bluish stripe runs from the eye to the caudal peduncle, typically forming 2-5 round spots. There is a suggestion that it is not a direct relative of other Laubuka and may warrant its own genus.

The butter catfish, Ompok bimaculatus, is a widespread silurid catfish recorded from Afghanistan and Pakistan east to China and Indonesia. Also known as the two spot glass catfish, it very likely contains a number of separate species, given the clear morphological differences between populations. It grows to 45 cm, needs a very large tank and will eat any smaller fish it can fit in its mouth.

Opsarius ardens is a fast-swimming cyprinid from the Sita and Swarna river systems of the Western Ghats in Karnataka, southwestern India. Before its description it was usually identified in the trade as O. canarensis. A row of bluish-green vertical markings along the body and broad orange margins on the dorsal and anal fins distinguish it. It lives in well-oxygenated, moderate to fast-flowing rivers and streams.

Opsarius bakeri is a fast-swimming cyprinid endemic to the Western Ghats of southwestern India, with records from many rivers in Kerala and Karnataka. It is traded as 'royal danio', 'blue-spotted hill trout' and 'blue-dotted mirror fish', and has a single row of bluish-green spots that get smaller with age. Its well-oxygenated, fast-flowing rivers are being polluted and degraded by exotic species and sand mining.

Traded as 'striped hill trout' or 'banded hill trout', Opsarius barna is a cyprinid from the Ganges and Brahmaputra basins in northern India. It is thought to also occur in the Mahanadi and in river systems in Nepal, Bhutan, Bangladesh and Rakhine State, Myanmar, in well-oxygenated, fast-flowing rivers over gravel, cobbles and boulders. An extremely fast swimmer and vigorous feeder, it is unsuitable for the general community.

Barilius bendelisis is a large, fast-swimming cyprinid from India, Bangladesh, Nepal and probably Bhutan. Occasionally sold as 'Indian hill trout' or 'Hamilton's baril', it has 8 to 12 bluish vertical bars and, in adults, a blue-black spot on each scale. It grows to around 200 mm SL and inhabits well-oxygenated, fast-flowing rivers and streams, and its speed and vigorous feeding make it unsuitable for the general community.

Opsarius canarensis is a cyprinid from southwestern India, known with certainty only from the Netravathi and Tungabhadra river systems in Karnataka. Its name has historically been applied in the trade to O. ardens and O. malabaricus, and it was redescribed in 2015. Two rows of bluish-green spots and broad white margins on the dorsal and anal fins distinguish it. It inhabits well-oxygenated, fast-flowing rivers and streams.

The Manipur baril, Opsarius dogarsinghi, is a cyprinid from the Chindwin river system in Manipur and Nagaland, northeastern India, and Myanmar. It occasionally appears in the trade as 'Burmese hill trout' or 'striped hill trout'. A large dark blotch at the caudal-fin base and 8-9 dark blue vertical bars help separate it from congeners, and it has been bred in aquaria.

The Malabar baril, Opsarius gatensis, is a cyprinid endemic to the Western Ghats of southern India, in Karnataka, Kerala and Tamil Nadu. Occasionally seen in the trade, it has 13 to 15 dark blue vertical bars that often almost break up in adults. It inhabits well-oxygenated, fast-flowing rivers and streams, apparently favouring slower runs and pools, and its speed and vigorous feeding make it unsuitable for the general community.

Opsarius malabaricus is a cyprinid from southwestern India, known with certainty only from the Payaswini and Valapattanam river systems in Kerala. Before its revalidation in 2015 it was usually traded as O. canarensis or O. bakeri 'orange fin'. Bluish-green spots along the body and broad orange margins on the dorsal and anal fins distinguish it. It probably inhabits well-oxygenated, fast-flowing rivers and streams.

Opsarius shacra is a cyprinid from the Himalayan foothills of Nepal and northern India, in the Ganges and Brahmaputra systems, and from Bangladesh. Poorly known in the hobby but exported on occasion, it has around 12 vertical bars on each flank and a black band in the upper third of the dorsal fin. It inhabits well-oxygenated, fast-flowing rivers with gravel, cobble and boulder substrates, and is too fast and vigorous a feeder for the general community.

Oreichthys cosuatis is a small cyprinid probably restricted to the Ganges and Brahmaputra River basins in Nepal, India and Bangladesh. Several undescribed Oreichthys spp. from India, Myanmar and Thailand continue to be traded under its name, and apparent records from those places likely represent other species. It lacks a black blotch on the caudal peduncle, and adults have a dark triangular blotch in the anal-fin.

The drape fin barb, Oreichthys crenuchoides, is a small cyprinid possibly endemic to Brahmaputra tributaries in West Bengal, eastern India. The species is sometimes traded as Oreichthys cosuatis, O. sp. 'high fin', Puntius 'arunavii' or 'neon highfin barb'. Males have a significantly enlarged dorsal-fin, and a large black marking at the caudal-fin base with no dark marking in the anal-fin separates it from congeners.

The Indian ricefish, Oryzias dancena, is widely distributed through eastern and southern India, Sri Lanka, Bangladesh and Myanmar. Mostly coastal but adaptable, it has been collected from strongly brackish mangrove swamps to acidic freshwater forest streams. It continues to be misidentified as O. melastigma, a name most recent workers consider invalid, or as O. javanicus, a valid but distinct taxon.

Osteochilichthys nashii is a cyprinid endemic to India, where it appears restricted to Karnataka and Kerala in the southwest. Predominantly a riverine fish, it lives in clear, well-oxygenated running water and hill streams over boulders, bedrock and smaller stones. Reaching around 18 cm, it is very scarce in the trade and most likely to turn up as a contaminant among imports of other Indian species.

The zipper loach, Paracanthocobitis botia, is a nemacheilid loach from the Brahmaputra River in Assam, northeastern India. It was long thought to range from Pakistan to western Thailand, and several populations once included under the name are now treated as separate species. Relatively hardy and peaceful, it is one of the better choices for those new to nemacheilids, and its dark, eye-like ocellus at the top of the caudal peduncle is normally more intense in younger fish.

Paracanthocobitis mooreh is a nemacheilid loach known only from the Godavari, Krishna and Kaveri (Cauvery) systems in western and southern India. An incomplete lateral line ending near the pelvic-fin origin, with small, mostly vertical blotches along it connected to the dorsal saddles, separates it from congeners. It favours stretches of streams and small rivers where leaf litter collects over sand, cobbles and boulders, and is generally non-aggressive.

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 aurea is a small cyprinid known from ponds in South 24 Parganas District, West Bengal, in the Ganges delta of northern India. Considered a phenotype of the similar P. gelius before its description, it has a yellowish-golden body, a broad black band around the caudal peduncle and a black blotch beneath the dorsal-fin origin. Very peaceful but timid, it does best in a group of at least 8-10 alongside other diminutive species.

Pethia canius is a small cyprinid from West Bengal in northern India, with recent collections from Cooch Behar and Nadia districts. Long considered a synonym of the closely related P. gelius, it had its identity settled and a neotype designated by Knight (2013). It inhabits ponds and other still-to-sluggish waters, and its small size and timid nature mean it does best alone or with other diminutive species.

The rosy barb, Pethia conchonius, is a small cyprinid found from Pakistan throughout India, Nepal and Bangladesh. Generally considered one of the hardiest small cyprinids in the hobby, it is an excellent choice for newcomers. Wild specimens are not usually available and the vast majority are commercially bred, with long-finned, 'veil-tail', 'super red', 'neon' and 'golden' strains among the forms selective breeding has produced. Feral populations exist in several countries.

The golden dwarf barb, Pethia gelius, is a small cyprinid native to the Ganges and Brahmaputra river drainages of northern India and Bangladesh. Records suggest a wider range, including Tamil Nadu and the Ayeyarwady delta in Myanmar, though the latter may warrant investigation. Knight (2013) settled its identity, revalidating P. canius and describing P. aurea, both previously treated as phenotypes of P. gelius. Very peaceful but timid, it does best alone or with other diminutive species.

The glass barb, Pethia guganio, is a small cyprinid widespread in the Ganges and Brahmaputra river systems of Bangladesh, Nepal and northern India. It lives in slow-moving or standing waters such as pools, ditches and minor rivers. Poorly known in the hobby, it shares its stiff, serrated last dorsal-fin ray, incomplete lateral line and 36-39 lateral scales only with Puntius nangalensis.

Pethia manipurensis is a small cyprinid apparently endemic to Loktak Lake in Bishnupur District, Manipur state, northeastern India. The species is considered endangered with a declining population trend, though it is bred commercially for the aquarium hobby. Males carry orange-red pigmentation on the flanks and caudal fin, as in P. meingangbii and P. padamya, but its humeral marking is a small spot where both of those have a large, vertically-elongated one.

Pethia nigripinnis is a small cyprinid of cool, flowing hill streams in Kerala and Tamil Nadu, apparently endemic to the southern Western Ghats. Adult males have black dorsal, anal, pelvic and pectoral fins. Its need for cooler temperatures makes it unlikely to suit the general community aquarium, and it will probably do best alone or with comparably-sized species needing similar conditions.

The dwarf barb, Pethia phutunio, is a small cyprinid from the lower Ganges and Brahmaputra river basins in Bangladesh and India. Frequently misidentified and quite rare in the trade, it is sometimes called 'spotted-sail barb' or 'spotted-tail barb'. Several congeners share its two black flank blotches, but it is smaller than all of them at 25 to 30 mm. It inhabits sluggish rivers, streams, ponds and swamps, often over deep mud or silt.

The Pookode Lake barb, Pethia pookodensis, is a small cyprinid described from Pookode Lake in Wayanad district, Kerala, and possibly endemic there. Pookode is a small forest lake and tourist destination that has suffered some degradation, and the IUCN classify the species as 'Critically Endangered'. It is most similar to P. ticto and P. punctata, with two dark flank markings, one on the front of the body and one on the caudal peduncle.

Pethia punctata is a small cyprinid endemic to the Western Ghats of southwestern India, where it appears restricted to west-flowing rivers. Poorly known in the hobby, it has a confusing taxonomic history and has been treated as both a synonym and a subspecies of P. ticto. It has a complete lateral line, two dark body blotches with the front one a scale row below the lateral line, and rows of spots in the dorsal fin.

The Narayan barb, Pethia setnai, is a small cyprinid common in rivers draining the Western Ghats of India, described from Sanguem in Goa. It is widely traded as 'Puntius' narayani, though the trade fish all have the serrated dorsal-fin spine of P. setnai, a feature 'P.' narayani lacks. The central of its three dark flank markings, beneath the dorsal fin, is uniquely pale and diffuse. In hill streams and smaller rivers it gathers in backwater pools and deeper, slower areas.

The Shalyni barb, Pethia shalynius, is a small cyprinid that appears to be endemic to Meghalaya state in northeastern India. It is known from only a handful of localities in the Khasi and Jaintia hills, mostly streams above 1200 metres with cool, clear, well-oxygenated water, and is apparently under threat from industrial activity. Very peaceful, it is still a poor choice for the general community aquarium because of its preference for cooler temperatures.

Pethia sharmai is a small cyprinid known only from a handful of localities around Chennai in Tamil Nadu, India. It mostly inhabits ponds and lakes, many of them in urban areas under pressure from urbanisation. Very peaceful but small and timid, it does best alone or with other diminutive species, and it is almost unheard of in the hobby outside India.

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.

The ticto barb, Pethia ticto, is a small cyprinid widely distributed through most of the Indian subcontinent, from Pakistan and Nepal to Bangladesh. Its name is frequently misapplied to P. padamya in aquarium literature, though P. ticto is much the less colourful fish and males lack reddish-orange pigmentation on the body. Morphology and colour pattern vary by population, and some populations have already been described as distinct species.

The Malabar leaffish, Pristolepis marginata, is a nandid endemic to the Western Ghats of Kerala, India, and is also known as the common catopra. Unlike many other nandids it inhabits flowing water, from fast-moving streams and rivers to some whitewater areas. It reaches 15 cm, will swallow any tankmate small enough to eat and can be a little belligerent, so it is best kept with similarly sized or larger fish that also suit flowing water.

The orange chromide, Pseudetroplus maculatus, is a euryhaline cichlid native to peninsular India and Sri Lanka. It mostly inhabits brackish estuaries, coastal lagoons and the lower reaches of rivers, and can be kept in fresh or brackish water so long as acidic conditions are avoided. Wild examples are rarely seen in the hobby, where selectively bred strains traded as 'red' or 'yellow' chromide are widely available.

The spiketail paradisefish, Pseudosphromenus cupanus, is a small labyrinth fish restricted to southern India and Sri Lanka. It lives in sluggish and still waters such as rice paddies, swamps and weedy ponds. It lacks the two dark lateral stripes of its only congener, P. dayi. A secretive bubble nester, it is peaceful but too small and timid for most community aquaria.

The brown spike-tailed paradise fish, Pseudosphromenus dayi, is a small labyrinth fish from coastal drainages of the Western Ghats in Kerala, India. It is known only from the Chalakkudy, Muvattupuzha and Periyar rivers, though it may be more widely distributed. Two dark, irregular lateral stripes on the head and body, and a more extended caudal fin in males, separate it from its only congener, P. cupanus. A secretive bubble nester, it is peaceful but small and timid.

The two-spotted barb, Puntius bimaculatus, is a small cyprinid from Sri Lanka and southern India. It lives in flowing hill streams and quieter stretches in the middle reaches of rivers, but tends to be absent from lowland environments. Also called the 'redside barb', it has 7 branched dorsal-fin rays and round dark spots at the base of the dorsal and caudal fins. Generally very peaceful, it is a schooling species and at least 6-10 should be kept.

The swamp barb, Puntius chola, is a cyprinid from much of Pakistan, India, Nepal, Bhutan, Bangladesh, Sri Lanka, Myanmar and western Thailand. Sometimes called the 'chola' or 'green' barb, it has a single pair of barbels and dark blotches behind the operculum and near the caudal-fin base. It apparently prefers stiller waters over mud or silt, and makes an ideal addition to a peaceful community of riverine fishes.

Puntius mahecola is a cyprinid from rivers draining much of the Western Ghats mountains in Kerala, Karnataka and Tamil Nadu states, southern India. The name was misapplied to members of Dawkinsia for over a century, while the fish itself was widely misidentified as P. amphibius. A relatively plain fish, it has a single dark blotch on the caudal peduncle behind the anal fin. D. assimilis and other Dawkinsia species appear on trade lists as 'mahecola barb'.

The maharaja barb, Puntius sahyadriensis, is a cyprinid endemic to the northern and central Western Ghats mountains of India. It lives in hill streams shaded by the forest canopy and dense marginal vegetation, over boulders, stones, sand or gravel. The angular body, colour pattern and enlarged male dorsal fin make it difficult to confuse with any other member of the genus, and it is occasionally traded as the 'Khavli' barb.

The onespot barb, Puntius terio, is a cyprinid widely distributed from Pakistan through northern India, Nepal and Bangladesh. Its range covers parts of the Indus, Ganges and Brahmaputra drainages, where it apparently prefers stiller waters over mud or silt. Populations vary in colour pattern to an extent, but all share a diffuse yellow-golden marking on the operculum and a dark spot on the caudal peduncle.