This study aimed to evaluate replacing fish meal with graded levels of silage made from fish by-products to feed monosex males of Nile tilapia (Oreochromis niloticus). Three diets were formulated in which fish meal was replaced by fish silage (0,25,50,75, and 100%). Diets were fed to experimental groups of tilapia for 120 days. The highest total weight gain TWG (49.93 g) was recorded for fish fed the control diet (SFB0) followed by those fed the diet SFB25% (44.01g/fish), SFB50% (43.08g/fish), SFB75% (38.65g/fish) and SFB100% (36.38g/fish), respectively and the differences in weight gain among the different fingerling groups were significant (P>0.05). Moreover, the same observation was noticed for specific growth rate SGR. In addition to that, the average feed intake and feed conversion ratio and protein efficiency ratio of Nile tilapia were significantly (P<0.05) affected by the incorporation of fermented fish meal as a substitute of fish meal. The carcass composition parameters of body composition was significantly altered while no significant differences were found among all studied groups concerning the moisture content. Replacing up to 75% of FM by SFB neither affected growth performance nor health state of tilapia but, economically decreased costs of production. Even though replacing up to (100%) was economically favored and gave good growth performance but it was a source of parastic infestation adversely affecting the health condition of tilapia and was cosmopolitan rendering fish esthetically unaccepted for human consumption.