Abstract: 4 isonitrogenous and isoenergetic test diets were studied.The control diet contained only fish meal as the sole protein source.Fish Protein Hydrolysate(FPH) was used to partially replace fish meal.The replacement levels were 17%,34% and 51% of the fish meal protein,respectively.Larvae cobia(Rachycentron canadum) with an initial weight of(3.79?.22)g were randomly stocked in triplicate groups in 300L indoor flow-system tanks fed with the test diets for 6 weeks.No significant differences in survival were observed among dietary treatments(P0.05).The results showed that the percent weight gain(WG) and feed intake(FI) were also positively linearly correlated to dietary FPH percentage,except the replacement levels were 51% of the fish meal protein group was the lowest.In conclusion,the tested FPH replacement fish meal protein 34% proved an efficient growth and feed intake stimulant in larvae of cobia Rachycentron canadum.Plasma total cholesterol concentrations increase with water FPH replacement fish meal protein,but the plasma total protein concentration did not have this regularity,among the dietary treatments groups the plasma triglyceride concentration were not significant(P0.05).