The present study was conducted to investigate the influence of dietary supplementation of root powder of Ashwagandha (Withania somnifera), flower powder of Butea monosperma, seed powder of Mucuna pruriens and dried powder of Jaiphal (Myristica fragrans) on gonadal maturity and milt quality in male brood stock of commercially important indigenous coldwater fish, snow trout, Schizothorax richardsonii in captive condition. Experimental fish of 3 years age were reared in FRP tanks (n=6) of 1200 L capacity with stocking density of n=60 in each tank and fed with control (CD) and experimental (TD) diets in duplicate at the feeding rate of 3-5% of their body weight twice a day. Gonadosomatic index (GSI) and Hepatosomatic index (HSI) were recorded for annual breeding cycle coupled with breeding indices and sperm density in breeding season along with regular monitoring of water quality parameters. In males, the GSI values ranges from 0.49 to 7.92 and 0.85 to 11.83 in control and treated groups, respectively. Two peaks of GSI values reflects the two breeding season of the species during the month of March and September. Similarly, HSI values vary from 0.41% to 0.52% and 0.44% to 0.58% in control and treated groups, respectively. In captive condition, 92% specimen were observed mature for spawning in treated group, while only 32% males were ready to oozing the milt in control stock. The fertilization rate (September 2019) was observed as 94.2% in treated group, while it was 86% in control group.The mean value of sperm count per ml. of milt (September 2019) was 3.64±0.66×10 8 /ml in control group and 4.44±0.64×10 8 /ml in treated group. The study revealed that 1.0 % supplementation of blend of herbs in the diet is beneficial for gonadal maturity in males and quality milt production of Schizothorax richardsonii in captivity under coldwater condition.