Achankovil

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.

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 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 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.

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 Malabar snakehead, Channa diplogramma, is a large snakehead endemic to the southern Western Ghats in Kerala and Tamil Nadu, India. Treated as a synonym of the Indochinese C. micropeltes for over a century, it was revalidated in 2011 and has 103-105 lateral line scales, more than any other Channa. Its colour pattern changes markedly with age, and unlike most snakeheads it is pelagic and needs plenty of room to swim.