Effect of seven artificial diets, having protein contents ranging from 10 to 48%, on the growth and food conversion in young Tilapia nilotica of mean weight 24 mg were tested in 0‰, 5 ‰, 10‰, and 15‰ salinities. Growth of young T. nilotica was consistently better on diets containing 28–30% protein. For diets up to 30% protein, the fish grew best at 10‰, and for diets of higher protein contents, fish grew best in fresh water. Efficiency of food conversion increased with dietary protein content up to 30% protein level and then decreased at higher contents. Food conversion efficiency was greater for young fish raised in 10‰ than in other salinities.