The Nile tilapia has distinctive, regular, vertical stripes extending as far down the body as the bottom edge of the caudal fin, with variable coloration. Adults reach up to 60 cm (24 in) in length and up to 4.3 kg (9.5 lb). It lives for up to 9 years. It tolerates brackish water and survives temperatures between 8 and 42 °C (46 and 108 °F). It is an omnivore, feeding on planktonas well as on higher plants. Introduced tilapia can easily become an invasive species (seeTilapia as exotic species). It is a species of high economic value and is widely introduced outside its natural range; probably next to theMozambique tilapia (O. mossambicus), it is the most commonly cultured cichlid. In recent research done in Kenya, this fish has been shown to feed on mosquito larvae, making it a possible tool in the fight against malaria in Africa.
The Nile tilapia typically feeds during daytime hours. This suggests that, similar to trout and salmon, it exhibits a behavioral response to light as a main factor contributing to feeding activity. Due to their fast reproductive rate, however, overpopulation often results within groups of Nile tilapia. To obtain the necessary nutrients, night feeding may also occur due to competition for food during the daylight hours. A recent study found evidence that, contrary to popular belief, size dimorphism between the sexes results from differential food conversion efficiency rather than differential amounts of food consumed. Hence, although males and females eat equal amounts of food, males tend to grow larger due to a higher efficiency of converting food to energy.
The Nile tilapia is an omnivore that feeds on both plankton and aquatic plants. It generally feeds in shallow waters, as harmful gases (such ascarbon dioxide, hydrogen sulfide, and ammonia) and temperature fluctuations found in deep waters create problems for the physiology of the fish. The Nile tilapia thrives on the warmer temperatures commonly found in shallow waters compared to the colder environment of the deep lake. In general, tilapias are macrophyte-feeders, feeding on a diverse range of filamentous algae and plankton.