Tilapia is the fifth most important fish in fish farming. Because of their large size, rapid growth, and palatability, tilapia are the focus of major farming efforts. Like other large fish, they are a good source of protein and popular among artisanal and commercial fisheries. Most such fisheries were originally found in Africa, but outdoor fish farms in tropical countries, such as Papua New Guinea, the Philippines, and Indonesia, are underway in freshwater lakes. In temperate zone localities, tilapia farming operations require energy to warm the water to tropical temperatures. One method uses waste heat from factories and power stations. China is the largest tilapia producer in the world, followed by Egypt.
Commercially grown tilapia are almost exclusively male. Cultivators use hormones, such as testosterone, to reverse the sex of newly spawned females. Because tilapia are prolific breeders, the presence of female tilapia results in rapidly increasing populations of small fish, rather than a stable population of harvest-size animals.
Other methods of tilapia population control are polyculture, with predators farmed alongside tilapia or hybridization with other species.
Whole tilapia fish can be processedinto skinless, boneless fillets: the yield is from 30 percent to 37 percent, depending on fillet size and final trim. The use of tilapia in the commercial food industry has led to the virtual extinction of genetically pure bloodlines. Most wild tilapia today are hybrids of several species.