Hydrobiology and fisheries of River Jia Bhorelli, a major tributary of Brahmaputra River was studied during January to June 2013. Jia Bhorelli River is a snow-fed River and is perennial one. The river is a major tributary of the River Brahmaputra. A total of 12 hydrological parameters were monitored. Some of the parameters showed slightly monthly fluctuation. A total of 61 fish species belonging to 44 genera, 20 families and 7 orders were recorded during the study period. The dominant family was found to be Cyprinidae followed by Siluridae, Perciformidae, Synbranchidae, Clupiformidae, Belontidae, Tetraodontidae and Anguillidae. The present paper deals with an extensive work on Fish diversity and Habitat ecology of the River Jia Bhorelli. Conservation status¹ of the recorded species was assessed.