Abstract:The Indian hill trout cyprinid, Barilius bendelisis is a member of family Cyprinidae that dwells in shallow, cold, and clear water. In this study, growth parameters and reproductive biology of Indian hill trout, Barilius bendelisis from river Gaula, Central Himalaya region, India, were studied. The length-frequency data were grouped sex wise and were analyzed to determine the growth and mortality parameters using the computer software programme, FAO-ICLARM Stock Assessment Tool (FISAT II). Altogether, 501 individuals were collected from river Gaula (November 2013-October 2014) and were preserved in formalin for further analysis. The results showed that the female outnumbered the male population. The minimum GSI of females was observed in the month of October (4.93 ± 0.26) and for males in the month of June and July (0.093 ± 0.12), whereas, the maximum value was in the month of April for both females (13.47 ± 0.52) and males (1.21 ± 0.12). Fluctuation in GSI values had a bimodal pattern showing two peaks during March-May and August-September in both the sexes, indicating the common spawning period of fish. The slope of regression showed the negative allometric growth for both males and females (b= 2.65 for male and b= 2.5 for female). A significant relationship between length and weight was observed in the present study (p < 0.05). The ELEFAN-I estimated L∞ and K of the von Bertalanffy growth factor for males (17.33 cm and 0.310 per year), females (17.33 cm and 0.3 per year) and pooled sexes (17.33 cm and 0.240 per year). The results indicated that Barilius bendelisis is a small sized fish having negative allometric growth that spawns twice a year. Thus, the present study on biological traits represents the baseline information for effective production, conservation and restoration planning. Rev. Biol. Trop. 64 (3): 1287-1295. Epub 2016 September 01.Key words: Barilius bendelisis, sex ratio, gonadosomatic index, river Gaula, India.The Indian hill trout cyprinid, Barilius bendelisis (Hamilton) is a member of family Cyprinidae, subfamily Danioninae, dwells in shallow, cold and clear water (Gurung et al., 2005). It is characterized by the pointed head, compressed body, blue/black vertical bands on the lateral side of body and origin of dorsal fin inserted behind the mid of the body (Talwar & Jhingran, 1991). This fish is an upland water fish, found in several countries of Southeast Asia such as India, Bangladesh, Nepal (Talwar & Jhingran, 1991), Myanmar, Pakistan, Thailand and Srilanka (Eschmeyer & Fricke, 2011). In India, this species is commonly distributed in Ganga and Brahmaputra drainages along the Himalayan foothills. Barilius bendelisis plays a considerable role in the capture fishery of the Himalayan parts of Arunachal Pradesh, inhabiting in lentic and lotic water bodies where other carps cannot be raised successfully (Sahoo, Saikia, & Das, 2009).Growth parameters are crucial for sustainable use and exploitation of aquatic macrofauna and their management (Yakub, 2010). Therefore, understanding the p...