After 15 days posthatching, the highest values of averageweight (1.97 g) and highest survival rate (93%) of tilapia wererecorded significantly (p < 0.05) in the fry treated with 60 mg17a-MT/kg diet compared to those of groups treated with 40,80 mg 17a-MT/kg diet or in the untreated control group. Onthe other hand, the lowest values of average weight (0.754 g)and lowest values of survival rate (65%) were recorded in tilapiatreated with 80 mg 17a-MT/kg diet (p> 0.05)