Muvattupuzha basin

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.

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.

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.