The present world production of tilapias is relatively low, despite their high potential for aquaculture. Most research efforts towards their husbandry have been aimed at solving the major problem in tilapia culture, uncontrolled reproduction. Other attributes of potential importance, such as temperature and salinity tolerance, feeding habits and growth capacity have been largely neglected. Real attempts at genetic improvement in tilapias have been restricted to the production of all-male hybrid progeny. A rational choice of species or isolates, according to economically important traits, instead of locally available species could be a first step in increasing production by genetic methods.