This study aimed to investigate the effect of dietary graded levels of three pre-and probiotics on the immunity and haematology of all-males mono-sex Nile tilapia fish. The experimental period was 16 weeks after 2 weeks adaptation period. In the pathogenicity test, dietary inclusion of Aqua Superzyme at 0.01% of the diet, Garlen Allicin at 0.01% of the diet, and Diamond V (XPC) at 0.5% of the diet, generally reduced the mortality rate (%) and therefore increased the survival rate (%). Yet, the only significant (P<0.05) positive effect was due to Aqua Superzyme at 0.01% of the diet in general and after 48h whereas the other supplements did not significantly (P>0.05) affect the pathogenicity. The comparisons among substances and their levels clear that the best survival was occurred in the treatment 1:1, i.e the fish group fed Aqua Superzyme (at 0.01% of the diet) diet. The haematological parameters' values increased significantly (P<0.05) by using Aqua Superzyme, particularly at 0.01% of the diet; Garlen Allicin, particularly at 0.01% of the diet; and Diamond V (Original XPC), particularly at 0.4% of the diet). Yet, the overall significantly (P<0.05) best valus for all tested parameters among additives and their levels was that contained Aqua Superzyme at 0.02% of the diet. So, it is recommended to supply Nile tilapia's diet with the prebiotic Aqua Superzyme at 0.01-0.02% of the diet to improve the immunity system of the fish.