Krishna basin

Barilius 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.

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 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.

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 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'.

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 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.

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.

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.

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 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 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 freshwater needlefish, Xenentodon cancila, is a belonid from Pakistan east through India, Bangladesh, Nepal, Sri Lanka, Myanmar and Thailand. Often called 'freshwater garfish', it only superficially resembles the true gars, and most of its relatives in the Belonidae are marine or estuarine. A near-exclusive inhabitant of the upper water column, it is surprisingly peaceful with anything too large to swallow and is best kept in numbers of four or more, in a tank of 180 ∗ 60 cm or more.

The grass carp, Ctenopharyngodon idella, is a large cyprinid native to the Amur River system in eastern Russia and northeastern China. Adults typically reach 800 to 1200 mm, making it a wholly unsuitable aquarium subject, though an albino form is traded. Widely introduced for aquaculture and weed control, it has caused serious damage to natural waters, and unwanted fish should never be released.

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.

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.