A feeding trial was conducted in a recirculating water system to investigate the effects of dietary protein levels on growth, feed utilization, hepatosomatic index and liver lipid deposition of juvenile red snapper, Lutjanus argentimaculatus (average initial wet weight 8.0±0.39g and total length 3.14±0.3cm). In the experiment, six fishmeal-based diets were formulated to contain various protein levels (20% to 45% in 5% increments), with dietary energy ranging from 2210.7kJ 100g to 2 250.2 kJ 100 g dry matter. The protein to energy ratios of diets ranged from 8.58 mg protein kJ-1 to 20.03 mg protein kJ-1. Diets were fed for 90d to triplicate groups of fish stocked in 0.128 m3 seawater tanks, 25 individuals each. The daily ration of 2% wet body weight was offered to the fish thrice a day. The fish at the end of the study had more than ten-fold (77.0g) in- crease in weight compared to the initial (8.0g). Fish fed diets of 40% and 45% protein produced significantly (P<0.05) higher weight gain of 77.2g and 76.5 g, and specific growth rate (SGR) of 2.65% and 2.62% than those of 67.0 g and 68.3 g, and 2.49% and 2.51% of the other diets. The broken-line regression of SGR against dietary protein level yielded an optimum dietary protein requirement of 42.6% (Y = - 1.6295 + 0.1114 AT2, P<0.05). Survival remained 100% among groups. Feed conversion ratio decreased from 0.45 for fish fed 20% dietary protein to 0.35 for fish fed 45% dietary protein. Nitrogen in- take increased with an increase in dietary protein, which in turn resulted in an increase in nitrogen gain of fish whole body. Fish fed 40% and 45% protein diets showed higher (P<0.05) nitrogen gain (0.27g and 0.26g) than those (0.23g and 025g) fed all other diets. Gross energy intake (GEI) in fish fed 45% protein was lower (600.67kJ) than that (607.97kJ) of 40% protein diet, though the differences were not statistically significant (P>0.05); GEI ranging from 677.31 kJ to 663.20 kJ at remaining four diets (20% to 35% protein) did not appear to differ significantly (P>0.05). The highest energy gain of 518.33 kJ was obtained with fish fed 40% protein, resulting in the highest energy retention efficiency of 85.26%. The hep- atosomatic index of fish fed diets of 20%, 25%, 30% and 35% protein were significantly (P<0.05) higher (2.09% to 2.57%) than those (1.44% and 1.41%) of fish fed diets containing 40% and 45% protein. Liver lipid contents decreased from 8.72% to 7.0% in fish fed dietary protein of 20% to 45% in 5% increments. Results suggest that the diet containing 40% to 42.6% protein with a P/E ratio of 17.6mg protein kJ-1 is required for good growth of L. argentimaculatus weighing between 8.0 g and 85.2 g under the culture conditions of the present study. A feeding trial was conducted in a recirculating water system to investigate the effects of dietary protein levels on growth, feed utilization, hepatosomatic index and liver lipid deposition of juvenile red snapper, Lutjanus argentimaculatus (average initial wet weight 8.0 ± 0.39g and total length 3.14 ± 0.3 cm). In the experiment, six fishmeal-based diets were formulated to contain various protein levels (20% to 45% in 5% increments) with dietary energy ranging from 2210.7 kJ 100 g to 2 250.2 kJ 100 g dry matter. The protein to energy ratios of diets ranged from 8.58 mg protein kJ-1 to 20.03 mg protein kJ-1. Diets were fed for 90d to triplicate groups of fish stocked in 0.128 m3 seawater tanks, 25 individuals each. The daily ration of 2% wet body weight was offered to the fish thrice a day. The fish at the end of the study had more than ten-fold (77.0g) in crease in weight compared to the initial (8.0g). Fish fed diets of 40% and 45% protein produced significantly (P <0.05) higher weight gain of 77.2 g and 76.5 g, and specific growth rate (SGR) of 2.65% and 2.62% of those of 67.0 g and 68.3 g, and 2.49% and 2.51% of the other diets. The broken-line regression of SGR against dietary Protein level yielded an optimum dietary protein requirement of 42.6% (Y = - 1.6295 + 0.1114 AT2, P <0.05). Survival remained 100% among groups. Feed conversion ratio decreased from 0.45 for fish fed 20% dietary protein to 0.35 for fish fed 45% dietary protein. Nitrogen-take increased with nitrogen increase of dietary protein, which in turn resulted in an increase in nitrogen gain of fish whole body. Fish fed 40% and 45% protein diets showed higher (P <0.05) (0.27 g and 0.26 g) than those (0.23 g and 025 g) fed all other diets. Gross energy intake (GEI) in fish fed 45% protein was lower (600.67 kJ) than that (607.97 kJ) though the differences were not statistically significant (P> 0.05); GEI ranging from 677.31 kJ to 663.20 kJ at remaining four diets (20% to 35% prot eiThe highest energy gain of 518.33 kJ was obtained with fish fed 40% protein, resulting in the highest energy retention efficiency of 85.26%. The hep-atosomatic index of fish fed diets of which 20%, 25%, 30% and 35% protein were significantly (P <0.05) higher (2.09% to 2.57%) than those (1.44% and 1.41%) of fish fed diets containing 40% and 45% protein. lipid content decreased from 8.72% to 7.0% in fish fed dietary protein of 20% to 45% in 5% increments. Results suggest that the diet containing 40% to 42.6% protein with a P / E ratio of 17.6 mg protein kJ-1 is required for good growth of L. argentimaculatus weighing between 8.0 g and 85.2 g under the culture conditions of the present study.