ABSTRACT This study investigated the effect of dietary amino acid composition from proteins alternative to fishmeal on the growth performance of the common snook, Centropomus undecimalis. Fish of 10.79±0.71 g (n = 150) were stocked in 15 shaded outdoor tanks of 1 m3. The basal diet contained 643.4 g kg−1 salmon byproduct meal (SML) and 200.0 g kg−1 soy protein concentrate (SPC). Two other diets replaced 39 and 29% of the SML with poultry byproduct meal (PBM, 170.1 g kg−1) and SPC (334.9 g kg−1), respectively. Fish were fed twice daily for 84 days under 32±1 g L−1 water salinity and 27.3±0.9 °C temperature. Final survival (99.5±2.6%) was unaffected by dietary treatment. Snook grew slower (0.24±0.03 and 0.27±0.04 vs 0.35±0.06 g day−1) and achieved the lowest body weight (31.1±6.62 and 33.3±10.20 vs 40.4±13.18 g) and the highest feed conversion ratio (3.69±0.29 and 3.11±0.51 vs 2.33±0.34) when fed SPC and basal diets compared with PBM, respectively. Retention of dietary crude protein varied from 36 to 38% for fish fed the basal and SPC diets, but exceeded 51% in fish fed PBM. Results indicate a greater ability of the common snook to gain weight and increase retention of nutrients when dietary protein is of terrestrial animal origin. Dietary protein from PBM yields a more balanced dietary amino acid composition relative to fish muscle, but possibly in excess of the species requirements.