The current study was performed to determine the impact of dietary protein level on the S. rivulatus performance under biofloc system conditions during the nursery phase. Three commercial diets with three dietary protein levels were evaluated; 25, 30 and 40 crude proteins (coded as 25CP%; 30CP% and 40 CP% diets, respectively). 135 fries with an initial weight of 0.76 ± 0.03g/fry were randomly stocked into nine experimental tanks at 15 fries/ tank. The experiment was extended for 60 days. Results showed that fish fed 40CP and 30CP diets recorded the highest significant weight gain and specific growth rate without significant difference between them. However, fish fed 25CP diet recorded the lowest performance. Histological examinations revealed mild changes in the intestines of fish fed 40CP diet, compared to fish fed 30CP and 25CP diets. While the gills and liver were not affected by the change in diet crude protein concentration. It could be concluded that 30% crude protein diets may be recommended to cultivate S. rivulatus under biofloc system conditions during the nursery phase.