The study aimed to determine the optimum dietary lysine level of orange-spotted rabbitfish Siganus guttatus Bloch, 1787 (average body weight range 5.2 7.6 gxfish-1). feeding trial was conducted for 8 weeks employing six experimental diets which were isonitrogenous, isocaloric, and isolipidic (35% crude protein (CP), 18.3 MJxkg-1 gross energy, 5% lipid). content ranged from 1.22 g 2.12 xkg-1 dry...