Mahseers, known as the king of rivers, are among the largest carp and a valuable group of freshwater fish in Asia. The word Mahseer has its origins in Bengal; the two root words, Maha, mean greatness and Seer, means mouth or head; literally, it means having a strong and large head. The range of these fish is across the entire Indian subcontinent. There are four genera of Mahseer, viz., Tor, Neolissochilus, Naziritor, and Parator, available across the world. Out of the 47 species of Mahseer that exist in the world, India is home to fifteen. They are game fish as well as commercially important and highly esteemed food fish. Mahseer fetches a high market price. But all the Mahseer carps belonging to all genera and species are under serious threat due to various anthropogenic activities. Mahseer is a sensitive species that can barely tolerate a modified water environment. It is a bioindicator organism. The population of Mahseer has seriously declined due to the degradation of the ecological conditions of aquatic systems, indiscriminate fishing of broodstock and juveniles, adverse impacts of river valley projects, industrial and human pollution, use of explosives, poisons, and electrofishing by poachers, the introduction of exotic species, and population pressures on resources. Rejuvenating the freshwater bodies and in-situ conservation are needed for replenishing the declining population of Mahseer. The Tata power plant at Lonavla developed standard techniques of Mahseer breeding through decades of study. Till date, it has produced in excess of 10 million fingerlings of Mahseer and distributed them all over India. Its findings on breeding methods have proved valuable and have even been replicated in several Mahseer breeding facilities across the country.