Environmental variability has a great impact on the processes of ecological organization. Local variation probably accounts for population variation in the death rate. Marine parasites are of great importance. Incorporating environmental variation into theories of life histories for a better understanding of how environmental factors influence physiology and the resulting histories of individuals. Adult Oreochromis auruis were collected from, El Behiara, Egypt. The concentration of  Pb, Cu, and Cd have been detected in the biota samples collected from El Behara, Egypt. The plenty of heavy metal concentration in the fish samples was found in the order   Cu > Pb > Cd. A significant correlation (p < 0.05) was found for each of Cu, Cd, and Pb in Oreochromis auruis.  The mean level of Pb is highly positively correlated with the mean concentration level of the activity of GPx and the mean level of the total protein as r= 0.51 and r= 0.61; while Cu is highly positively correlated with Cd, S‰ and the total protein as r=0.75, r=0.65, and r=0.74; respectively. Cd is only highly significantly correlated with the total protein as r= 0.64. The salinity was highly correlated with both pH and the total protein as r=-0.64 and r=0.6; respectively. The mean value of pH is highly negatively correlated with both GPx and with the total protein as r= - 0.50 and r=-0.52; respectively. The activity of GPx is highly correlated with only the activity of the SOD as r=- 0.701.