The North East region shares its fish fauna predominately with that of the Indo- Gangetic fauna and to a small extent with Burmese and South China fish fauna. Out of a total number of about 20,000 fish species estimated to occur throughout the world, more than 200 species are found in the Brahmaputra drainage system. In fact, the Brahmaputra and Barak river systems of Assam sustain substantial diversity of fish germplasm and is therefore considered as one of the hotspots of freshwater fish biodiversity. Surveys indicate the existence of 306 fish species in this region, which is amounts to approximately 33.13% of the total extant Indian freshwater fishes. In Jeypore Reserve Forest, 71 species of fish belonging to 21 families and 48 genera were recorded in a preliminary survey of the River Buridihing and its tributaries in the forest landscape including the Tipam, Dilli and smaller forest streams and beels. The dominant families are Cyprinidae, Bagridae, Schilbeidae and Cobitidae, with the cyprinid fishes constituting the major group of fish fauna, accounting for 40% of the total species recorded. Four species are endangered, while 14 species are considered Vulnerable and 36 species are Near Threatened. Common fish genera in Jeypore include Labeo, Barilius, Puntius, Aspidoparia, Phylorinchus, Raimas, Danio, Salmostoma, Cirrhinus, Salmostoma, Erethistes and Rita. Jeypore provides a wide diversity of micro habitats for fish. Rocky, fast-flowing streams have fish such as Psilorhynchus balitora, Acanthobotitis botia, Lepidocephalus guntea; while streams with moderate current and sand-pebble beds are home to species like Devario devario, Danio dangila, Danio aequipinnatus and Raiamus bola. Deep pools with sandy beds provide shelter to species like Rita rita, Notopterus notopterus, Salmostoma bacila, Cirhhinus reba etc. and the shallow streams with gravel beds and rooted macrophytes harbour species such as Erethistes hara, Botia Dario and Psilorhynchus balitora. The rivers have a few deep pools locally called doobis where relatively larger sized fish like Rita, Cirhhinus, Labeo, Wallago, Clupisoma, Sperata dwell and feed year round. Fish swim into the small, usually seasonal rivulets that empty into the Buridehing river during the rainy months to forage and possibly breed there. Some of the fishes that are special to Jeypore include the Olyra longicaudata, locally known as tulaji or pahari singhi because it is found in hilly areas; Psilorhyrhynchus balitora, locally known as balitora; the rare carni-omnivorous Raiamas bola, locally known as korang whose coloration of greenish grey dorsally and silvery on the belly is excellent camouflage in the rainforest habitat it occupies. Other interesting fish in Jeypore are Danio aequipinnatus and the migratory, carnivorous Anguilla benghalensis, locally known as nagbami which is an endangered species. The Buridehing is also on the travel itinerary of a pod of 3 or 4 endangered Gangetic dolphins that swims upstream several kilometres, most likely from the Brahmaputra every year during high flood season. There is a record of a young dolphin caught in a fisherman's net a few years ago, but for the most part they are left unharmed during the weeks the dolphins hunt fish in the doobis.