Abstract: 7 sem-i purified diets formulated with casein and white fish meal as protein sources to contain graded levels of protein ranging from 32. 07% to 45. 64% were fed to Erythroculter ilishaef ormis ( initial weight 2. 88? 0. 22g#ind- 1 ) in triplicate for 8 weeks. The feeding trial was conducted in fiberglass tanks in which the water temperature during the feeding was controlled from 25e to 29e . The results showed that the weight gain, specific growth rate, feed efficiency and protein efficiency ratio of fish fed a test diet with 41. 05% cr ude protein on dry basis were significantly higher ( P < 0. 05) than tho se of the rest gro ups. Based on quadratic model regression analysis of SGR and FE, it was found that the optimal protein requirements were 40. 94% and 41. 35% of dry diet respectively. Moreover, there was no significant effect of dietary protein levels on who le body moisture, protein and ash( P> 0. 05) , but its body lipid decreased ( P < 0. 05) when the fish were fed 2 diets with high levels of dietary protein at the end of the feeding trial.