Protein deficiency is one of the major problems facing world today. Nowadays, fish considered as the main important and favorite source of animal protein for human consumption. In Egypt, the continuous increase in human population requires more food production to meet their demand. Fish is a commodity of potential public health concern as it could contaminated with a wide range of environmentally persistent chemicals, including heavy metals and parasitism. No doubt, that fish harbor a wide range of ecto- and endo-parasites infecting the alimentary canal, liver, kidney, reproductive organs, muscles as well as gills and skin. Most helminth parasites carried by fishes are Nematodes, Acanthocephala, Cestodes and Trematodes. Nematodes are nature aquatic organisms live as internal parasites in fish. Recent observations indicate that various nematode species respond differently to degradation of environmental quality thus the degree of nature change in the community structure of aquatic nematodes may be an excellent indicator of water quality or pollutant levels.