The main objectives of our study were as follows:(1)to examine the current pollution status of metals (Al,Cd,Pb,Hg and Ni)in water and some organs of Oreochromis niloticus fish collected from illegal fish farm;(2)to study the concentrations of metals in organs of collected farmed fish;(3)to evaluate the effects of chronic fish exposure to metals on the health of farmed fish, which was determined through the application of histo-pathological examinations of fish organs.Moreover,as this species is of economic importance,metal concentrations in fish muscles were compared with the maximum permissible international limits in order to ascertain the suitability of these fishes to human consumption and to elucidate possible adverse human health effects associated with the consumption of fish originating from illegal farms.