Loaches

Acanthocobitis sinuata is a nemacheilid loach from peninsular India, described from Wayanad district in Kerala. It appears widespread in drainages south of the Krishna. Most authorities treat it as a synonym of A. mooreh, but the two differ in distribution, dorsal-fin ray count and colour pattern, and they are apparently being revalidated. Both have a reduced lateral line ending around the dorsal fin, which in the similar A. botia is complete or ends above the anal fin.

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

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

Acanthopsoides sp. 'A01' is an unidentified dwarf horse-face loach of unknown origin, likely to be collected in Thailand or Peninsular Malaysia. Like several of its congeners in the trade it has proven very tricky to identify. It spends some of its time completely buried, so it needs a soft, sandy substrate, and it is best kept in a group of six or more. SF member Mark Duffill has recovered fry from an adult pair kept on their own in a small tank.

Acanthopsoides sp. 'A02' is an unidentified dwarf horse-face loach of unknown origin, likely to be collected in Thailand or Peninsular Malaysia. Like several of its congeners in the trade it has proven very tricky to identify. A soft, sandy substrate is essential because it spends some of its time completely buried, and it is highly gregarious and best kept in a group of six or more.

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 hasselti is a cobitid loach described from Java and recorded from Myanmar to Vietnam, Peninsular Malaysia, Sumatra and Borneo. Its wide distribution makes it relatively common in the aquarium hobby. Colour and pattern vary with locality and have led to problems with identification, and the flanks usually show a row of dark blotches or a solid stripe with a light, unpigmented stripe above.

Lepidocephalichthys kranos is a cobitid loach from the Chao Phraya system in Thailand and the Mekong in Thailand, Laos and Vietnam. Some private collectors have kept it. Its colour pattern tends to form a mosaic, unlike the irregular spotting of most congeners, and the body deepens steeply behind the snout to give a 'hunched' appearance. It can often be found living with L. hasselti.

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 large-scaled loach, Misgurnus dabryanus, is a 'true' loach from the Yangtze and Pearl rivers in China, plus Taiwan and the Amur in Russia. It is sold regularly in the hobby but almost always labelled as or mixed in with M. anguillicaudatus, from which it differs in its high adipose crests on the caudal peduncle and the lack of a dark spot at the caudal-fin base. It spends some of its time completely buried, so it needs a soft, sandy substrate.

The giant kuhli loach, Pangio myersi, is a barred cobitid loach from the lower Mekong basin in Laos, Cambodia, Vietnam and Thailand. Traded regularly and also known as 'Myer's loach', it has 8-11 very broad dark bars on an orange body. A submarginal dark bar or row of spots on the caudal-fin separates young or undernourished imports from P. kuhlii and P. semicincta. Albino and leucistic forms are also available, though it is unclear whether these occur naturally.

The black kuhli loach, Pangio oblonga, is a plain-bodied cobitid from Java, Sumatra, Borneo, Peninsular Malaysia and Thailand. Among the more readily available Pangio in the hobby, it is also traded as 'Java loach', 'cinnamon loach' and 'chocolate kuhli loach'. The species will probably turn out to be a complex of closely-related taxa, with at least four genetic lineages identified.

Usually sold as the 'kuhli' loach, Pangio semicincta is a cobitid loach from Peninsular Malaysia, Sumatra and Borneo. It lives in shallow forest streams and swamps, often in black water, and is typically abundant in leaf litter. P. kuhlii itself is currently considered endemic to Java and has possibly never been seen in aquaria, so the common aquarium 'kuhli' is more likely to be this species or an unidentified relative.

Pangio shelfordii is a variably patterned kuhli loach from Peninsular Malaysia, Singapore, Sumatra and Borneo. Its patterning varies within and between populations, and as currently understood the species represents an assemblage containing a number of unidentified taxa. Some Sumatran and Bornean populations resemble P. piperata, which often occurs alongside it. It is exported occasionally, often as bycatch among shipments of congeners.

Pangio sp. 'PAN01' is an unidentified kuhli loach, possibly from Borneo, assigned to the P. kuhlii-oblonga group with a degree of certainty. The imported fish shown in the profile do not correspond to any described Pangio. Some carry a pinkish to purplish pigmentation that has also been reported in P. superba and appears to be shared by some Bornean Pangio populations.

Pangio sp. 'PAN02' is an unidentified kuhli loach of unknown origin that can be assigned to the P. kuhlii-oblonga group with a degree of certainty. It is apparently exported as a contaminant among shipments of a uniformly brown fish, and unpublished genetic analyses suggest the two might be variants of the same species. Its dark upper and white lower body suggest it may be related to P. alcoides.

Pangio sp. 'PAN03' is an unidentified kuhli loach that appears to be native to the Barito River basin in Indonesian Borneo. It belongs to the P. kuhlii-oblonga group and has been misidentified and traded as P. alternans, a different-looking species. Like its congeners it needs a soft, sandy substrate, since it digs and spends some of its time buried.

The panda loach, Pangio sp. 'PAN04', is an unidentified kuhli loach apparently native to the Thai portion of the Mekong River basin. Traded since the mid-00s, it comes in two similar forms. One has a darker body, dark pectoral fins and barbels and a blue sheen on the head, while the other is paler with better-defined head markings, hyaline pectoral fins and colourless barbels.

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.

The Inle loach, Petruichthys brevis, is a small nemacheilid loach known only from Lake Inlé and its watershed in Shan state, eastern Myanmar. Sometimes traded as 'Lake Inle red-tailed loach', it is listed as 'Vulnerable' on the IUCN Red List due to deterioration of the lake. Unlike most loaches it spends a lot of time in the open, often hovering in midwater, and it is highly gregarious, needing a group of at least 8-10.

The fork-tailed loach, Vaillantella maassi, is a loach from Sumatra, Borneo, Peninsular Malaysia and southern Thailand. Traded as 'chocolate scissor-tailed loach' and 'dragon loach' among other names, it has a bluish-brown body with an orange to yellow dorsal stripe. Rarely traded in numbers, it is among the more reclusive loaches and can be aggressive with its own kind and other fishes.

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 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 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 black-lined loach, Ambastaia nigrolineata, is a botiid loach from the Mekong drainage in southern China and Laos, and the Nan River in Thailand. It resembles its only congener A. sidthimunki but has a solid dark lateral stripe and another along the dorsal mid-line, with the vertical bars between them much less prominent. In Thailand it is considered endangered and appears in the national Red Book of threatened species.

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.

Annamia cf. thuathienensis is a hillstream loach described from the Bô River in Thua Thien-Hue Province, central Vietnam. Its description was published in Vietnamese and very little is known about it: some major resources do not list it as valid, and Kottelat (2012) considers it a 'species inquirenda'. Its ecology should be similar to that of A. normani, which lives in riffles and rapids over rocky substrates.

The Vietnamese giraffe loach, Annamia normani, is a hillstream loach from Mekong tributaries in Vietnam, Laos and Cambodia and from coastal Vietnam. An obligate resident of riffles and rapids, it has been traded as the 'Vietnamese lizard loach' and 'Vietnamese Homaloptera'. Adults studied in the Duc My River were specialised grazers of cyanobacteria. Many of its known habitats are threatened by planned hydroelectric projects.

Balitoropsis zollingeri is a balitorid loach described from Java and recorded from Sumatra, Borneo, Peninsular Malaysia, Thailand, Laos and Cambodia. An obligate dweller of swiftly flowing streams and headwaters, it lives on riffles and runs over gravel, rocks and bedrock carpeted with biofilm. It needs clean, well-oxygenated water with strong turnover in the aquarium. It lives in aggregations in nature and is less bold when kept singly or in small numbers, so a group of six or more is best.

Beaufortia cyclica is a hillstream loach known from a handful of localities in the Xi River drainage and the Tuoniang river system in southern China. Its flattened head and body and horizontal paired fins form a sucking cup that lets it cling to rocks in shallow, fast-flowing, highly-oxygenated headwaters. Kottelat (2012) states that B. cyclica may be a synonym of B. elongata.

The butterfly loach, Beaufortia kweichowensis, is a hillstream loach from the Xi Jiang (West River) system in southern China. In many countries it is the most common gastromyzontid in the shops, one of several loaches traded as 'butterfly loach', 'Hong Kong plec' or 'Chinese hillstream loach' regardless of species. The name B. leveretti is often applied to it. It needs clean, well-oxygenated, fast-flowing water, and 16 to 24 °C is recommended.

Beaufortia szechuanensis is a hillstream loach from the upper Yangtze River basin in Sichuan province, southwestern China. It has been recorded from several tributary systems including the Qing, Wu and Da Ning He. Its flattened head and body and horizontal paired fins form a sucking cup that lets it cling to rocks in shallow, fast-flowing, highly-oxygenated headwaters.

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.

The polka-dot loach, Botia kubotai, is a botiid loach that appears to be endemic to headwaters of the Salween basin in Myanmar and Thailand. It was traded before it was described and is still sold as 'angelicus', 'Burmese border loach' and 'marbled loach', among other names. Juveniles are often confused with B. histrionica, but the dark bars in B. kubotai split at a young age.

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 emperor botia, Botia udomritthiruji, is a botiid loach known only from the Tanintharyi River drainage in southern Myanmar. Known since 1993, it was occasionally traded as B. sp. 'Tenasserim' before it was described. At first glance it is most easily confused with B. histrionica but keeps its wider vertical bars at all ages, while in B. histrionica the bars become irregular or break up completely as the fish mature.

The clown loach, Chromobotia macracanthus, is a large botiid loach native to river systems of Borneo and Sumatra in Indonesia. Widely sold, it is wholly unsuitable for smaller aquaria: a group needs a tank of at least 180 x 60 cm, and a properly kept fish can live for more than twenty years. Bornean and Sumatran populations differ slightly in pattern, and in the Batang Hari, Sumatra, drifting larvae are now collected and grown on for the trade.

Erromyzon sinensis is a gastromyzontid loach from the Xi Jiang (West River) system in southern China, mostly in Guangxi. It is extremely rare to nonexistent in the aquarium trade, although its name has been widely misapplied to congeners such as the unidentified E. sp. 'ER02'. An obligate bottom-dweller, it lives in shallow, fast-flowing, highly-oxygenated headwaters and minor tributaries, clinging to rocks with its flattened body and horizontally-orientated paired fins.

Erromyzon sp. 'ER01' is an unidentified gastromyzontid loach, probably native to the Xi Jiang (West River) system in southern China. Its range is unconfirmed: the fish pictured arrived as a contaminant in a shipment of Beaufortia kweichowensis. It appears somewhat similar to Erromyzon yangi. Like its congeners it needs the clean, well-oxygenated, fast-flowing water of shallow headwaters and minor tributaries.

Erromyzon sp. 'ER02' is an unidentified gastromyzontid loach from southern China, traded as Erromyzon sp. 'red spots'. Other trade names include 'Strawberry Spot Sucker Loach', and it has also been sold as a Gastromyzon or Pseudogastromyzon species. No other Erromyzon is known with a dark base colour, thin paler vertical bars on the body and similar spots on the head, and older fish develop red spots along the lateral line.

The tasseled-mouth loach, Formosania lacustris, is a gastromyzontid from Taiwan and some coastal drainages of Fujian Province, mainland China. An obligate dweller of swiftly-flowing streams and headwaters, it clings to rocks in riffles and runs using its flattened head and body and horizontal paired fins. The genus was formerly Crossostoma, and colour and pattern vary with locality and age.

Gastromyzon aeroides is a hillstream loach endemic to northern Borneo, recorded from western Sabah in Malaysia and the Temburong basin in Brunei. The dorsal, caudal and anal fins are blue in life, and the plain brown body separates it from the other two species in the G. punctulatus group. Like its congeners it needs swift, clean, well-oxygenated water.

Gastromyzon cornusaccus is a small hillstream loach known only from the Sungai Kinarom, a river draining Mount Kinabalu in Sabah, Malaysian Borneo. Before its description it was often misidentified as G. danumensis because of its small adult size and secondary rostrum. Juveniles have thick cream bars and blotches, while adults are uniformly coloured. Like its congeners it needs swift, clean, well-oxygenated water.

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

Gastromyzon extrorsus is a hillstream loach from the Kimanis and Petagas basins, draining the western Crocker Range in Sabah, Malaysian Borneo. The brown body carries up to nine thin gold stripes and the head a gold reticulate pattern. Growing to around 80 mm SL, it lives in swift, shallow streams with clear, oxygen-saturated water, and in aquaria needs clean, well-oxygenated water with strong turnover.

Gastromyzon farragus is a small gastromyzontid loach from swift hill streams in the Sadong River basin of southern Sarawak, Malaysian Borneo. It is dark brown with thin cream bars across the back and a red caudal fin, and is very close to G. ocellatus. One of the more commonly traded members of the genus, it often arrives in mixed shipments labelled 'Borneo sucker' or 'Hong Kong pleco', and needs clean, well-oxygenated water with strong flow.

Gastromyzon introrsus is a hillstream loach known only from the Padas and Labuk basins, draining the eastern Crocker Range in Sabah, Malaysian Borneo. The brown body has up to 12 cream vertical bars, and it grows to around 95 mm SL. It lives in swift, shallow streams with clear, oxygen-saturated water, and in aquaria needs clean, well-oxygenated water with strong turnover.

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

Gastromyzon monticola is a hillstream loach from streams draining Mount Kinabalu into Marudu Bay, and the Wariu basin, in Sabah, Malaysian Borneo. It has a spotted back with wavy bars on the flanks and grows to around 85 mm SL. German aquarist Philipp Dickmann attempted to spawn it and published his observations in 2001. Like its congeners it needs swift, clean, well-oxygenated water.

Gastromyzon ocellatus is a small hillstream loach known only from the Sarawak River drainage in southern Sarawak, Malaysian Borneo. One of the more commonly traded members of the genus, it turns up in mixed shipments labelled 'Borneo sucker', 'Hong Kong pleco' or 'butterfly loach'. The dark brown body has cream bars that break up into an ocellus pattern on the flanks, and the caudal fin is red in life.

Gastromyzon scitulus is a hillstream loach endemic to tributaries of the Sungai Sadong basin in southern Sarawak, Malaysian Borneo. One of the more commonly-traded members of the genus, it usually arrives in mixed shipments labelled 'Borneo sucker' or 'Hong Kong pleco' regardless of species. It forms a pair of cryptospecies with the very similar G. ctenocephalus, and intermediate forms of both mean identification can sometimes be tricky.

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

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

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

Gastromyzon sp. 'SK04' is an undescribed hillstream loach from South Kalimantan province, Indonesian Borneo. Based on colour pattern it appears similar to members of the G. lepidogaster group, which also includes G. psiloetron. It has occasionally been maintained by private collectors, and like its congeners it needs clean, well-oxygenated water with strong flow.

Gastromyzon stellatus is a hillstream loach from the Sarawak, Sadong and Lupar River drainages in southern Sarawak, Malaysian Borneo. Its dark brown head and body carry many small yellow spots. It forms a pair of cryptospecies with G. zebrinus and is often confused with it, since both show intermediate colour patterns. One of the more commonly-traded members of the genus, it usually arrives in mixed shipments labelled 'Borneo sucker' or 'Hong Kong pleco'.

Gastromyzon viriosus is a hillstream loach known only from the Tatau River drainage in central Sarawak, Malaysian Borneo. A dark brown body with 8-10 complete vertical cream bars and a thin, cream, reticulated pattern on the head identify it. It is occasionally seen in the trade, most often in mixed shipments labelled 'Borneo sucker', 'Hong Kong pleco' or 'butterfly loach' regardless of species.

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

Hemimyzon formosanus is a balitorid loach endemic to Taiwan, most abundant in rivers draining the western slopes of the Central Mountain Range. Current knowledge suggests it is the most widely distributed of the three Hemimyzon species endemic to the island. It lives in shallow, fast-flowing, highly oxygenated headwaters and needs clean, well-oxygenated water, a biologically mature tank with plenty of biofilm, and a tight cover since it can climb glass.

Hemimyzon nanensis is a balitorid loach known only from the upper Mae Nam Nan river basin, part of the Chao Phraya system in northern Thailand. It was the first member of the genus recorded outside China and Taiwan. At the type locality it was collected in shallow riffles over algae-covered stones, and in the aquarium it needs clean, well-oxygenated water and a biologically mature set-up.

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.

Homaloptera ogilviei is a small 'lizard' loach recorded through much of the Malay Peninsula in both Malaysia and southern Thailand. Quite rare in the trade, it is sometimes imported as bycatch and sold as 'lizard' or 'gecko' loach. Its paired fins are orientated vertically, unlike those of other members of the genus, and in aquaria it perches on the tips of its fins at rest. It favours slower stretches among plants, roots or leaf litter.

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

Homaloptera parclitella is a 'lizard' loach from Peninsular Malaysia and the Sai Buri, Bang Nara and Kolok river systems of southern Thailand. It was previously considered a form of H. orthogoniata and may be seen identified as such online and in print. It always has two large, saddle-shaped markings on the back, where H. orthogoniata has three, and it lives in swift, clear, oxygen-saturated streams.

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.

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

Homalopteroides smithi is a hillstream loach from Thailand, Peninsular Malaysia and parts of the Mekong basin in Laos, Cambodia and Vietnam. Perhaps the best-known member of the genus, it is relatively common in the aquarium hobby, and Rainboth (1996) considered it 'probably the commonest member of the genus in the Mekong'. An obligate dweller of swiftly-flowing streams and headwaters, it needs clean, well-oxygenated water.

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

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

Homalopteroides weberi is a hillstream loach from Sarawak in Malaysian Borneo, described from the Akar River and possibly endemic to the state. Poorly known in the aquarium hobby, it was questioned as a possible synonym of Balitoropsis stephensoni by Kottelat (2012), but Randall and Page consider it distinct. It inhabits swiftly-flowing streams and headwaters with clear, oxygen-saturated water.

Homalopterula gymnogaster is a hillstream loach from Sumatra, Indonesia, described from Lake Maninjau and recorded from Jambi province northwards. Tan and Kottelat (2009) describe it as a relatively common highland species of riffles and 'quiet waters'. That makes it unusual, since Homaloptera species are not normally associated with standing water, though it remains unclear whether the fish come from the lakes themselves or their outflowing rivers.

Homalopterula ripleyi is a hillstream loach known only from a small area of northern Sumatra, Indonesia, on the eastern slopes of the Barisan range. Fowler (1940) described it from a single specimen as the only member of his new genus Homalopterula. Gerhard Ott and Dirk Dettmers collected it in 2003 for the first time in over 60 years, from small, clear forest streams over bedrock, boulders, rocks and gravel.

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

Iksookimia hugowolfeldi is a cobitid loach endemic to Korea, known from the Yeongsan and Tamjin river systems in the province of Jeollanam-do. It is most similar to I. longicorpus, of which it was first considered a geographical variant, and has narrow dark bars below the lateral line with densely arranged small spots above. It apparently prefers small, shallow rivers and streams with moderate to fast currents, and needs clean, well-oxygenated water.

Iksookimia koreensis is a cobitid loach endemic to Korea, relatively common in river drainages of northern and western South Korea. It is most similar to I. pumila, formerly treated as a subspecies, but has 10 or more dark bars on each flank, saddle-like markings along the back and irregular spots over the upper body. It apparently prefers small, shallow rivers and streams with moderate to fast currents, and needs clean, well-oxygenated water.

Iksookimia pumila is a small cobitid loach endemic to Korea, known only from the Baek River drainage in the south-west of the country. A dam built in the middle reaches of the river in the late 1990s has undermined its presence at some localities. It is most similar to I. koreensis, of which it was formerly considered a subspecies, but has fewer than 10 bars on each flank and only a few larger, vertically orientated blotches on the upper body.

Iksookimia yongdokensis is a cobitid loach endemic to Korea, known from four river drainages in the eastern province of Gyeongsangbuk-do. Most similar to I. longicorpus and I. hugowolfeldi, it has 9 to 13 dark vertical bars on the flanks, a small dark spot at the base of the upper caudal-fin lobe and a much smaller lamina circularis in males. It is most often seen in sluggish, shallow habitats with sand or pebble substrates in the mid-to-upper sections of rivers.

Jinshaia sinensis is a balitorid loach known only from the Jinsha river basin, the westernmost headwater tributary of the Yangtze in China. Like other balitorids it has a flattened head and body and horizontally extended paired fins that form a powerful sucking cup. It lives only in riffles, runs and cascades of swift, clear, oxygen-saturated water, and the aquarium must be set up to resemble such a habitat.

Kichulchoia multifasciata is a cobitid loach known only from river basins of southwestern Korea. It is restricted to shallow, fast-flowing, highly-oxygenated headwaters with riffles and runs, and needs clean, well-oxygenated water in the aquarium. It is most easily told from K. brevifasciata, its only congener, by its body patterning, wrinkled lips and short barbels.

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

Kottelatlimia katik is a miniature cobitid loach from Johor in Peninsular Malaysia and the Batang Hari drainage of Sumatra, reaching 13.5 mm SL. It is considered paedomorphic, keeping juvenile features such as long fins and long nasal barbels into adulthood. It lives in small forest streams associated with blackwater peat swamps, often in leaf litter, and needs a soft sandy substrate and spotless water.

Kottelatlimia pristes is a small cobitid loach from Peninsular Malaysia, Sumatra and Borneo, the most widely-distributed member of its genus. It inhabits small, slow-moving forest streams and peat swamps with tannin-stained water, often in piles of leaf litter. It turns up occasionally in the trade, sometimes as bycatch among other species and under names such as 'Sumatran mini royal loach' or Cobitis cf. sumatranus.

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.

The Loktak loach, Lepidocephalichthys irrorata, is a small cobitid from north-eastern India and Bangladesh. Hora described it as widely distributed in lakes and streams of the Manipur Valley, and some of his specimens came from Loktak Lake. It grows to only 29 mm SL, has large, exposed scales on top of the head, and is occasionally exported as bycatch among other species.

Lepidocephalichthys furcatus is a small cobitid loach from Peninsular Malaysia, southern Thailand and North Sumatra, Indonesia. Not traded often, it turns up occasionally as bycatch among shipments of other species. It is told apart from congeners most easily by the prominent, roughly semi-circular lamina circularis in males, a feature unique within the genus, and it has a forked caudal fin.

Lepidocephalichthys jonklaasi is a cobitid loach endemic to the 'wet zone' of south-western Sri Lanka, known from at least five localities. Records exist from the Gin, Kalu, Nilwala and Bentota river basins plus a small blackwater creek near the Kottawa Forest Reserve. Its conservation status perhaps precludes its suitability for the hobby. Broad dark bars on the caudal fin and large, vertically elongated black spots on the flanks identify it.

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.

The Vietnamese marbled hog-faced loach, Lepidocephalichthys sp. 'LE1', is a cobitid loach from central Vietnam. Unconfirmed reports suggest it is collected in the coastal province of D'Nang. It has been traded only a handful of times and referred to as Lepidocephalichthys cf. hasselti and Lepidocephalus cf. thermalis, but appears to be an undescribed member of the former genus.

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 tomaculum is a small cobitid loach from Peninsular Malaysia, with a single tentative record from Lampung Province, Sumatra. It inhabits shallow, slow-moving streams, swamps, oxbows and backwaters over mud, silt or peat. Occasionally available as bycatch, it has a reddish brown body with thin dark bars across the back, and where it lives with L. hasselti identification can be difficult.

Lepidocephalichthys zeppelini is a tiny cobitid loach from the Mekong system in Thailand and Vietnam and the Chao Phraya drainage in central Thailand. Adults reach only 25.8 mm SL, and the lamina circularis of mature males forms a large, finely serrated flange. Many adults at the type locality were collected from remnant ephemeral pools in otherwise dry agricultural land.

Lepidocephalus macrochir is a cobitid loach described from Sumatra and since recorded from Thailand, Peninsular Malaysia, Java and Borneo. It is traded sporadically as the 'pinky loach', 'deep water kuhli loach' and 'Borneo high body cave loach'. Although sometimes said to be a cave loach, Thai collectors report it from deep water, and in aquaria it spends a lot of time buried in soft substrates.

Leptobotia guilinensis is a botiid loach from southern China, described from Guangxi Province and also recorded from neighbouring Hunan. The species is rarely exported for the aquarium hobby, and fish labelled as such are usually Sinibotia pulchra or other related species. In the formal description Chen states that it is closely related to the fish now called Sinibotia zebra but lacks stripes on the head. Its habitat is unconfirmed but presumably clear, well-oxygenated running water over rocks and gravel.

Leptobotia microphthalma is a botiid loach from the upper Yangtze basin in southwestern China, known from the Min and Jialing rivers. Its near-vestigial eyes and the variable hypopigmentation seen in many individuals suggest a deep water or even subterranean existence. Poorly known in the hobby, it is superficially similar to L. tientainensis and differs in a more deeply forked caudal-fin and a smaller eye, although eye size varies considerably between individuals.

Leptobotia pellegrini is a botiid loach from southern China, described from Sichuan province and also known from the Pearl River (Zhu Jiang) basin. Often traded as 'royal clown loach', a name also applied to L. elongata, it differs from that species chiefly in adult size, reaching around 200 mm SL against 500 mm. It is also more slender with a darker head, and its relatively wide distribution probably explains why it is commoner in the hobby.

Leptobotia rubrilabris is a riverine botiid loach native to the middle and upper Yangtze River in China, with most records from Sichuan and Hunan. Fish labelled as this species in the trade are typically Sinibotia pulchra or other related species. In nature it favours clear, well-oxygenated running water over rocks and gravel, from boulder-filled headwater streams to larger, turbid river channels, and much of the Yangtze has been degraded by dam construction and pollution.

Leptobotia taeniops is a botiid loach native to the middle and upper Yangtze River in China, recorded mostly from Hunan including Dongting Lake. Poorly known in the hobby, it is available occasionally and normally traded as 'honeycomb loach'. It exists in a number of colour forms from plain to reticulated and brown to pink, with reticulated populations towards the eastern end of its range, and it was previously included in the related genus Parabotia.

The broken-band hillstream loach, Liniparhomaloptera disparis, is a gastromyzontid from the Pearl River system of southern China and from Hong Kong. It is restricted to shallow, fast-flowing, highly oxygenated headwaters with riffles and runs. Sometimes available as bycatch among shipments of Rhinogobius duospilus, it also appears on trade lists under the fictitious name 'Homaloptera hoffmani'. It has been bred in aquaria and buries its eggs within the substrate.

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.

Microcobitis misgurnoides is a small cobitid loach from central Vietnam and the Mekong system in eastern Laos, growing to 41 mm SL. It was described in Cobitis and stayed there for over 60 years until Bohlen and Harant (2011) moved it to the new genus Microcobitis. It apparently lives in groups, and a soft, sandy substrate probably suits it best.

Micronemacheilus cruciatus is a small nemacheilid loach that appears to be endemic to the coastal rivers of Vietnam. It is traded under names including 'Vietnamese multi-banded zebra loach' and 'hovering zebra loach', and its colour pattern is a dark lateral stripe with numerous vertical cross-bars. It can be susceptible to swings in water chemistry and should not go into a biologically immature aquarium.

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 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 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.

The Laos blackline torpedo loach, Nemacheilus longistriatus, is a nemacheilid loach from the Mekong in Thailand and Laos. It has been collected from the main river channel and from backwaters over bedrock or sand. It is occasionally exported for the aquarium hobby and is told apart from the similar N. binotatus by the dark saddles along its back. A naturally reclusive loach, it becomes more confident alongside schools of peaceful, open water-dwelling cyprinids.

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 ornatus is a small nemacheilid loach known only from the Tapi river drainage in Surat Thani province, southern Thailand. It is said to occur in shallow riffles with clear, moderately-flowing water over small pebbles. Its colour pattern is a black lateral stripe with 9-16 vertical blotches extending above and below it, and the first of these blotches is ringed with lighter pigment to form an ocellus.

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.

Nemacheilus platiceps is a nemacheilid loach native to the Mekong basin in Laos, Thailand, Cambodia and Vietnam, and the Dong Nai system. It has been collected from shallow, slow-moving hill stream pools where leaf litter collects, and from faster-flowing stretches over gravel. It is only occasionally available in the aquarium trade and has 12-16 dark, irregular body bars, usually split vertically.

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

Nemacheilus selangoricus is a nemacheilid loach ranging from southern Thailand through Peninsular Malaysia and Singapore to western Borneo and Sumatra. It is most common in shallow, flowing forest streams over sand, gravel and detritus. It belongs to the N. selangoricus group and is most similar to N. spiniferus, from which it differs in its 8-12 very regular dark bars on the flanks.

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

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.

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

The ajime loach, Niwaella delicata, is a 'true' loach that appears restricted to river drainages of central Honshu, Japan. It lives in shallow, fast-flowing, highly-oxygenated headwaters and minor tributaries, and retreats to streams or underflows to remain dormant between October and April. In Japan it is a prized food fish. A dark stripe or row of blotches along the lateral line separates it from its congeners.