Vitamins are organic compounds essential for growth, health condition and protecting the body against many diseases (Vitamin-deficiency symptoms) in the most organisms including fish. Vitamin C has been to be necessary for the formation of tooth, bone, anhatching larvae were used to investigate the optimal treatment conditions for fish masculinity procedure by either immersion in 17a-methyl testosterone or infeeds. The results of these experiments could be summarized as :The results concluded that Tilapia (Oreochromois niloticus) which fed on50 mg vit C/kg diet recorded the best values of growth performance andhealth condition, in comparison with those of the other experimentalgroups. On the other hand, these results were noticed many clinicalsymptoms in the individuals which received vitamin C deficient diets asanorexia, retardation in growth, exophthalmia, changes in colour(depigmentation of skin), abnormalities of their behavioral responses (lostof reflexes), did not react to external agitation, can be easily caught, andtheir escape movement was not energetic.