Arunachal Pradesh being rich in fishery resources biophysically, the status of the fish diversity is not known from all the water bodies. A case study was undertaken in the river Siyom (28°11′25′′-28°10′52′′N and 94°45′17′′-97°47′51′′E) of West Siang district, Arunachal Pradesh from 2002 to 2004 with the fragmentary work till 2007. For the purpose, sampling of fish was done from the river time to time using local contraption along with modern nets. A total of 44 species of fishes belongs to 9 families were identified. Fishes of family Cyprinidae were found to be dominant followed by Balitoridae. Some of the fish species were found very rare in the river, which may be due to various anthropogenic factors. Therefore, in addition to social restriction on community fishing some awareness measures need to be taken to prevent the destructive fishing activities in the river. DOI: 10.3126/on.v8i1.4324
