1. The taxonomic classification of tilapia is still confusing and subject of continuous modification. Currently, tilapia are divided into three genera, Tilapia (substrate spawners), Sarotherodon (maternal/paternal mouth brooders) and Oreochromis (maternalmouthbrooders).
2. Tilapias are freshwater groups of fish species originated exclusively from Africa (excluding Madagascar) and from the Middle East ( Jordan Valley and coastal rivers). They are distributed all over Africa, except the northern Atlas Mountains and south-west Africa.
3. The genus Tilapia is widely distributed in West and Central Africa, but not in the eastern slope of the eastern Rift Valley and the river basins flowing into the Indian Ocean north of the Zambezi River.
4. The genus Sarotherodon, except S. galilaeus, is restricted to West Africa, while S. galilaeus spread eastwards towards the Nile and the first Rift lakes.
5. Fishes of the genus Oreochromis are distributed more in the Central and Eastern African regions, but they are rare in western Africa.
6. Outside Africa, tilapia are widely distributed in South and Central America, southern India,Sri Lanka and Lake Kinneret (Israel).
7. Several tilapia species have been introduced into many countries, both in Africa and outside Africa, for various objectives. Many introductions were successful, but many others were unsuccessful or successful but had negative side effects.
8. Feeding and dietary preferences of tilapias depend on tilapia species and size, time of day, photoperiod, water depth and location, with little selectivity.
9. Tilapia of the genus Oreochromis are primarily microphages, feeding mainly on phytoplankton, periphyton and detritus.
10. Tilapia of the genus Sarotherodon are also primarily phytoplanktivorous, but they are more selective.
11. Tilapia of the genus Tilapia are generally macrophyte feeders. They also ingest algae, phytoplankton, zooplankton, invertebrate larvae, fish eggs, insects, bacteria and detritus that are attached to the macrophytes.
12. Feeding patterns and efficiency of tilapia may be subject to diurnal and seasonal changes. Generally, tilapia feed intensively during early morning and late afternoon and reduce feeding at midday and at night.
13. The digestive system of tilapias is relatively simple and unspecialized, consisting of a very short oesophagus, a small, sac-like stomach and a very long intestine. Such a digestive tract reflects the herbivorous feeding habits of tilapia.
14. Tilapia have two types of teeth, jaw teeth and pharyngeal teeth. Both types of teeth vary from one tilapia species to another to suit the different diet preferences.
15. Microphagous tilapia have numerous, long, thin, closely spaced gill rakers, while tilapia that feed on large particles have fewer, large gill rakers.