TThe second fed on balanced diet supplemented with inulin (5 g kg−1), whereas, the third one received a balanced diet supplemented with vitamin C (500 mg kg−1). The survival and growth performances were evaluated. Blood samples were collected from the experimented tilapia, one and two months from the onset of the experiment to measure the hematocrit (HCT) values, nitroblue tetrazolium (NBT), and lysozyme activity. The protective effect of the two compounds was evaluated via challenge infection using pathogenic Aeromonas hydrophila.