Oreochromis niloticus (Nile Tilapia) is native to the basins of the River Nile, and westward to Lake Chad, and the basins of the Rivers Chad, Senegal, Gambia, Volta, Benue, Chari and Niger. It has been widely introduced around the world for aquaculture, in Mexico, the West Indies, Central and South America, central and South Africa, Asia, from Sri Lanka to Taiwan, and Pacific islands. It has been introduced to 88 countries and is established in at least 51. It is primarily a freshwater fish, but tolerates salinities up to 30 PSU, though tolerance varies among populations. Oreochromis niloticus regularly hybridizes with other species, especially O. aureus, both in aquaculture, and in the wild. Hybrid populations are widespread in Florida. and have also been found in coastal Louisiana and Mississippi. Nile Tilapia are established in several bayous of the Pascagoula River, in Mississippi adjacent to aquaculture operations, Survival of Oreochromis niloticus in the Mississippi Sound system is made possible by warm effluents from aquaculture facilities and power plants, Other populations, in the Chicago Sanitary and Ship Canal, and the Susquehanna River, in Pennsylvania have been at least temporarily established in n the thermal effluents. Estuarine populations of O. niloticus have been reported in waters of Central and South America, America, in Pacific and Caribbean estuaries of Costa Rica and Colombia (Caribbean), and are widespread in coastal waters of Brazil.