Chauhan, R.S.Singh, Ranjeet2019-01-222019-01-222018-06http://krishikosh.egranth.ac.in/handle/1/5810091947The study was conducted to access the “Effect of 17-alpha methyl testosterone on sex reversal and growth in fry of swordtail, Xiphophorus helleri” in aquarium for a period of 3 months. The experimental work was carried out in Wet Lab of the College of Fisheries, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar. Twelve glass aquaria of size 4.0 ft x 1.0 ft x 1.0 ft with the average water depth of 0.65 ft (water volume 80 litres) were used in the experiment. Four treatments with three replications were made. One hundred and twenty fries (0.005 g; 0.49 cm) were divided into 12 groups, having 10 fries in each. To observe the health status and growth, measurement of fishes in terms of weight and length by sampling was done at every 15 days interval. During the study period, the physico-chemical parameters of water samples from all experimental aquaria were analyzed weekly. Sex reversal and survival of fries were estimated at the end of the experiment. The various water quality parameters e.g. water temperature, dissolved oxygen, free CO2, pH and total alkalinity ranged within tolerance limit of the experimental fish. During the study period a significant role of hormone on fry was achieved. The rate of masculinization, 66.66% of male population was found in 90 mg/kg (H3) treatment tank where control showed 53.33% of male population. The rate of masculinization increased with increased hormonal application in a significant way. The maximum length was found in control (T0) treatment i.e. 1.44 cm and maximum weight was also found in control (T0) treatment i.e. 0.272 g. Minimum length and weight were found in H3 treatment group i.e. 0.99 cm and 0.074 g respectively. Length and weight of fishes was decreasing as the concentration of hormone was increasing. It shows that females are converting into males as we know males of swordtail are smaller in size than females.ennullThesis