Tilapia is an important food fish in many tropical and sub- tropical countries. It provides one of the most important sources of animal protein and income throughout the world. They are considered suitable for culture because of their high tolerance to adverse environmental conditions, relatively fast growth and the ease with which they can be bred Egypt has vast areas which can be best utilized for culturing tilapia, but The culture of tilapia is still beset with problems of their prolific breeding habit and stunted growth. In order to control breeding of tilapia and increase its body size, different strategies were made to prevent overcrowding and stunting; the culture of only males (mono-sex) is one of the most common techniques for preventing overcrowding and stunting by using steroid-induced sex inversion or by hybridization.