The Nile tilapia (Oreochromis niloticus) is one of the most commonly farmed tilapia species in the world. It is also commonly used for hybridisation to create tilapia variants even more suitable for farming in various conditions. The popular ND21 tilapia hybrid is for instance the result of breeding a female Nile tilapia of the ND-2 tilapia family line with a male Blue tilapia (Oreochromis aureus) of the ND-1 Tilapia family line.

Oreochromis niloticus is a fast growing species that can live in many different types of waters, from lakes and rivers to sewage canals. It is highly adaptable and can make use of a wide range of different food sources (including plants), but feeds primarily on phytoplankton and benthic algae. Even though the Nile tilapia is considered a freshwater species it has shown a great tolerance towards salt and can live in brackish conditions. In the wild, it inhabits a temperature range of 13.5-33 °C (56-91 °F)

The wild Oreochromis niloticus is dark coloured and many commercial tilapia farmers are therefore growing leucistic breeds instead, since the paler varieties tend to be more highly appreciated among consumers. A leucistic fish is characterized by reduced pigmentation. Leucism is similar to albinism but affects all type of skin pigment, not only melanin.

Since Nile tilapia is such a popular food fish, it has been deliberately or accidentally introduced to the wild in many different parts of the world. It can today be found on all continents except Antarctica. When farming tilapia it is important to prevent escapes and adhere to local regulations, because the adaptable and productive Nile tilapia can easily turn into a problematic invasive species. (This risk is not limited to Nile tilapia only, many species of tilapia can turn into pests outside their native region.)