Corbett is home to many species of freshwater fish. The Ramganga, Palain, Sonanadi and Mandal rivers, provide vital habitat and breeding grounds for them because of moderate temperature, low gradient, presence of deep pools and boulders and gravel on stream beds, and negligible pollution. Fish form a fundamental link in the food chain for many key species like the gharial, otters, fish-eagles, kingfishers, ospreys, storks, fish-owls, egrets, darters and pelicans.
The most celebrated of the fishes is the Golden Mahseer (Tor putitora), a large freshwater river fish belonging to the carp family. It has a magnificent appearance – sap green body with bright orange scales. Mahseer is considered to be one of the most prized fish for anglers all over the world.
Clean water, which is increasingly becoming rarer, is the prime habitat requirement for the mahseer. Its population has declined due to loss of habitat. Loss of breeding grounds also poses a threat because mahseer require shallow, clear, well-oxygenated water for spawning, which again is hard to find these days. Decline of mahseer is also due to construction of dams on their migratory routes, obstructing access to favoured spawning areas upstream. The Ramganga is one of the best-preserved rivers for mahseer in India. Other important fish species of Corbett are Goonch (Bagarius bagarius), Indian trout (Barilius bola) and Rohu (Labeo rohita)
Sustainable angling, as opposed to intensive fishing, benefits conservation of prized fishes like mahseer. Angling is allowed in certain areas in the buffer region of Corbett after taking permits from the Forest Department.