Mahseer is the common name used for the genera Tor, Neolissochilus, Naziritor and Parator in the family Cyprinidae (carps). The name is, however, more often restricted to members of the genus Tor. The range of these fish is from Vietnam in the east and China in the north, through Laos, Cambodia, Thailand, Malaysia, Brunei and Indonesia, and across southern Asia including the countries of India, Nepal, Bhutan and Bangladesh within the Indian Peninsula, plus Sri Lanka, Pakistan and Afghanistan. They are commercially important game fish, as well as highly esteemed food fish. Mahseer fetch high market price, and are potential candidate species for aquaculture. Several of the larger species have suffered severe declines, and are now considered threatened due to pollution, habitat loss, overfishing and increasing concern about the impacts of unregulated release of artificially bred stock of a very limited number of species.
The taxonomy of the mahseers is confusing due to the morphological variations they exhibit. In developing strategies for aquaculture and propagation assisted rehabilitation of mahseer species, resolution of taxonomic ambiguities is needed and adherence to IUCN stocking guidelines must be followed.
Mahseers inhabit both rivers and lakes, with some species believed to ascend into rapid streams with rocky bottoms for breeding. Like other types of carps, they are omnivorous, eating not only algae, crustaceans, insects, frogs, and other fish, but also fruits that fall from trees overhead.
The first species from this group were scientifically described by Francis Buchanan-Hamilton in 1822, and first mentioned as an angling challenge by the Oriental Sporting Magazine in 1833, soon becoming a favorite quarry of British anglers living in India.
The golden mahseer Tor putitora was previously believed to be the largest member of the group and one of the largest cyprinids; it has been known to reach in length and in weight, although specimens of this size are rarely seen nowadays.