Cauvery

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.

The Malabar baril, Barilius 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.

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.

Dawkinsia rubrotinctus 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 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.

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.

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 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.

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.

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 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 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 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.

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'.

Schistura denisonii is a nemacheilid loach from the Western Ghats of southern India, described from the Bhavani River in the Cauvery system. Widely referred to Nemacheilus, it matches the diagnostic characters of Schistura. The number and arrangement of its vertical body bars vary greatly, and whether it represents a complex of species or a single taxon remains unclear. Feisty, it is largely unsuitable for the general community aquarium.

Schistura kodaguensis is a small nemacheilid loach from the Western Ghats of Karnataka, India, confirmed only from a tributary of the Cauvery. It is not a well-known aquarium fish but is maintained by a number of Indian enthusiasts. The very similar S. nilgiriensis, also from the Western Ghats, has a black spot at the base of the dorsal-fin and lacks the rows of spots on the caudal-fin.

The goonch, Bagarius yarrelli, is a very large sisorid catfish recorded from the Indus in Pakistan east through Indochina to Sumatra and Borneo. Also known as the 'giant devil catfish' and 'sand shark', it reaches 1300 to 2000 mm and is fished for food across much of its range. That wide distribution appears doubtful, and Indian and Southeast Asian populations may prove not to be conspecific. It lives among boulders in the fast, turbulent rapids of large rivers.

The green chromide, Etroplus suratensis, is a euryhaline cichlid from peninsular India and Sri Lanka, growing to 350 mm SL. It mostly inhabits brackish estuaries, coastal lagoons and lower river reaches. Not especially popular in the hobby, it is an important food fish, and some populations have crashed through over-exploitation. In Sri Lanka's Negombo Lagoon Pseudetroplus maculatus has been seen acting as its cleaner while also eating its eggs and fry.

The porthole bagrid, Hemibagrus punctatus, is a catfish known only from the Cauvery (Kaveri) river system in southern India. The IUCN lists it as Critically Endangered (possibly extinct), and at its confirmed localities in the Kabini, Bhadra and Moyar systems it was last collected in 1998 or earlier. It has been available only very occasionally in the aquarium trade, and its flanks carry dark spots arranged in vertical columns.

The bronze featherback, Notopterus notopterus, is an air-breathing notopterid from the Indian subcontinent and Southeast Asia. Also called 'Asian knifefish' or 'ghost knifefish' in the trade, it grows to 600 mm and arguably has no place in the ornamental hobby given its adult size and specialised requirements. The single species in Notopterus is likely to represent a complex of closely-related species.

Dario urops is a badid from the Western Ghats of southwestern India, recorded from the Valapattanam and upper Cauvery systems in Karnataka and Kerala. Unlike the rest of the genus it occurs in southwestern India, grows to at least 28 mm SL, and has a conspicuous black eye spot on the caudal peduncle. Though described in 2012, it was first collected in the 19th century, when Day recorded Badis dario from 'Wynaad'.

Garra mullya is a cyprinid endemic to and widespread within peninsular India, in rivers including the Tapti, Narmada, Godavari, Krishna and Cauvery. It has been recorded from flowing headwater streams to low altitude main river channels, including polluted stretches, and at least some populations migrate upstream to breed. Wild fish feed on algae, diatoms and organic detritus.

Gymnostomus ariza is a cyprinid widely distributed from the Indus basin in Pakistan through India, Bangladesh and Myanmar. Growing to around 300 mm SL, it inhabits flowing streams and tributaries with clear water. It has a confusing taxonomic history, having been placed in Bangana, Cirrhinus and Labeo in recent years. It breeds in temporarily-inundated zones in the wet season and is also produced commercially for food.