author(s)
Ranjeet Singh, Rikhi Singh Chauhan, Tanuja Pandey and Paramveer Singh

abstract
This current experiment of 90 days was conducted to observe the comparative efficacy of 17 α methyl testosterone on Swordtail (Xiphophorus helleri) fry via different dose rate with the help of oral feed administration at wet lab of the College of Fisheries, G.B.P.U.A & T, Pantnagar India. During this whole experiment, we used twelve glass fabricated aquariums with a capacity of 80 liter (Dimensions 4.0 X 1.0 X 1.0 Feet) respectively. Initially, we stocked 120 fish fry of average weight of 0.005 gm in twelve experimental aquarium tanks with 10 numbers of fry in each experimental aquarium respectively. For this experiment we collected Swordtail fish fry from College hatchery. On the other hand, we selected commercially available fish feed for oral administration of 17 α methyl testosterone during this whole experiment. Throughout, the experiment we feed the fish fry @ 5% body weight with interval of 8 hours during day time. Besides this, we mixed commercial available feed with different dose rate of 17 α methyl testosterone like: 30 mg/kg, 60mg/kg and 90 mg/kg respectively. On the other side, we installed one control aquarium tank (T₀) for the comparative study with treatment aquarium tanks like; H₁, H₂ and H₃ respectively. After 90 days of this experiment, we observed efficacy of 17 α methyl testosterone with different dose rate on the masculinization of Swordtail fish fry like; under 90 mg/kg feed we observed maximum male percentage as compared to H₁ and T₀ respectively. Besides this H₃ has a minimum number of female percentage as compare to H₂ tank. Moreover, we observed a high percentage of male population in all treated aquarium tanks with 17 α methyl testosterone as compared to T₀ like; 66.66 %, 60.0 %, 56.66 % and 53.33 % respectively. During our experiment we observed it is crystal clear that 17 α methyl testosterone have satisfactory results on masculinization of swordtail as compare to control experimental aquarium tank respectively.