River or lake, India
Western Ghats rivers and the Kaveri
The fast hill rivers of the Western Ghats, home of the hump-backed mahseer of the Kaveri and many fish found nowhere else.
The Western Ghats run down India's west coast, and their monsoon-fed rivers hold some of the richest freshwater fish life in Asia, with many species found nowhere else. The Kaveri, which rises in Kodagu and flows east through Karnataka and Tamil Nadu, is famous for its mahseer. At Bheemeshwari and Galibore, where the river cuts through forest, anglers once came from around the world for the hump-backed mahseer.
The hump-backed mahseer
The hump-backed mahseer, a huge carp with a raised back and orange fins, is found only in the Kaveri basin. Fishing camps along the river practised strict catch and release from the 1970s and recorded fish of over 40 kg. In 2018 scientists confirmed its scientific name as Tor remadevii and found it had almost vanished, partly because the introduced blue-finned mahseer had spread through the river. It is now listed as Critically Endangered, and angling inside the sanctuary was later restricted.
Fish of the hills
The rivers of Kerala and Karnataka hold many endemic fish. The Denison barb, a red-striped minnow, became one of India's best-known aquarium exports, and collection from the wild hurt its numbers. The yellow catfish of Kerala, the Deccan mahseer and many loaches and barbs live in the same streams. The Kaveri is also the last refuge of the wild mrigal carp of the south. Dams, sand mining, pollution and invasive fish are the main threats.
Still to be written: Tor remadeviae, Tor khudree, Denison barb, Horabagrus brachysoma, Mrigal carp.