Minerals deficiency in aquatic animals disturbs the biological manners and physiological functions. Wheras, nanoparticles play an important role in aquaculture, as they serve as essential minerals to increase fish growth and supplementation in feeds since many practical feedstuffs contain low levels of these microminerals. Dietary supplementation of nanoparticles produces greater survival, growth, antioxidant levels and immunity of aquatic organisms including fish. In this study, the diet of the Nile tilapia Oreochromis niloticus was supplemented with different levels of selenium nanoparticles (SeNPs), magnesium (MgNPs), and a mix of both. Moreover, the growth, survival and body vitality  were evaluated after 50 days of feeding. During the experiment, the fish were fed diet of 30% crude protein twice a day. SeNPs,  MgNPs, and a mix of both were added to the control diet at different levels of 0.0 (control). The diet consisted of different concentrations: 1 (T1 Se, T1 Mg & T1 mix), 3 (T2 Se, T2 Mg & T2 mix), 5 (T3 Se, T3 Mg & T3 mix), 6 (T4 Se, T4 Mg & T4 mix),  and 7mg/ kg (T5 Se, T5 Mg & T5 mix) diet to feed the Nile tilapia fingerlings whose average initial weight was 4.0± 1.0g.  After a 2-week acclimation period, fish were randomly distributed into 16 glass tanks, each with a volume of 40 L, at a density of 25 fish per tank. The results indicate that the growth indices, feed efficiency and survival rate were significantly enhanced (P< 0.05) by incorporating a mix of Se-Mg NPs at a concentration of 6mg/ kg diet. In conclusion, the supplementation of both SeNPs and Mg NPs together in the diet of O. niloticus showed a higher growth rate than those which fed by each NPs separately. These findings have beneficial implications for the performance of the fish farming industry.