Oreochromis niloticus

The Nile tilapia, Oreochromis niloticus is a relatively large cichlid fish native to Africa from Egypt south to East and Central Africa, and as far west as Gambia. It is also native to Israel, and numerous introduced populations exist outside its natural range (e.g. Brazil).

It is also commercially known as mango fish, Nilotica or boulti. The first name leads to easy confusion with another tilapia that is traded commercially, the mango tilapia (Sarotherodon galilaeus).

Description
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 in length and up to 4.3 kg. It lives for up to 9 years. It tolerates brackish water and survives temperatures between 8 and 42 C.

It has been variously reported in the literature to be a plankton feeder, an omnivore, and to feed on higher plants to the extent it may be used in control of aquatic weeds. Introduced tilapia can, on the other hand, easily become an invasive species (see Tilapia as exotic species).

It is a species of high economic value and is widely introduced outside its natural range; probably next to the Mozambique tilapia (O. mossambicus), it is the most commonly cultured cichlid.

Aquaculture
Aquaculture of the Nile tilapia goes back to Ancient Egypt, where it was called ỉn.t and represented by hieroglyph K1 of the Gardiner List. As a logogram, this meant "a Nile tilapia". Used as a determinative (ideogram), it apparently signified Nile tilapia and/or flathead mullets which, like the tilapia, were commercially important fish, namely in the Nile delta: If used as part of a phonogram, it represented the sound ỉn:

In modern aquaculture, wild-type Nile tilapia are not too often seen, as their flesh has a dark color that is not much desired by many customers, and because it has a bit of a reputation of being a trash fish associated with poverty. On the other hand, they are fast-growing and give good fillets; leucistic ("red") breeds which have lighter meat have been developed and these are very popular.

Hybrid stock is also used in aquaculture; Nile × blue tilapia hybrids are usually rather dark, but a light-colored hybrid breed known as "Rocky Mountain White" tilapia is often grown due to its very light flesh and tolerance of low temperatures.

The Nile tilapia has recently been discovered in a small stream in central Arkansas. This invasive species may harm the other aquatic life present in this stream within the next few years, depending on how quickly it is able to reproduce and how adapted it is to competition with other aquatic vertebrates. Evidence supports the possibility that the Nile tilapia has established a strong breeding ground and will eventually endanger other fish species, possibly competitively exclude them.

Gastronomy
The red-hybrid Oreochromis niloticus is known in the Thai language as pla thapthim (ปลาทับทิม), meaning "pomegranate fish" or "ruby fish". This type of tilapia is very popular in Thai cuisine where it is prepared in a variety of ways.

The black and white striped tilapia pla nin (ปลานิล), meaning "Nile fish", is commonly either salted and grilled or deep-fried, and it can also be steamed with lime (pla nin nueng manao).

Nile tilapia, called بلطي bulṭī in Arabic, is (being native to Egypt) among the most common fish in Egyptian cuisine, and probably the most common in regions far from the coast. It is generally either battered and pan-fried whole (بلطي مقلي bulṭī maqlī [bʊltˤiː maʔliː]) or grilled whole (بلطي مشوي bulṭī mashwī [bʊltˤiː maʃwiː]). Like other fish in Egypt, is generally served with rice cooked with onions and other seasonings to turn it red.

Systematics

 * Baringo tilapia, Oreochromis niloticus baringoensis Trewavas, 1983
 * Oreochromis niloticus cancellatus (Nichols, 1923)
 * Oreochromis niloticus eduardianus (Boulenger, 1912)
 * Oreochromis niloticus filoa Trewavas, 1983
 * Oreochromis niloticus niloticus (Linnaeus, 1758)
 * Oreochromis niloticus sugutae Trewavas, 1983
 * Oreochromis niloticus tana Seyoum & Kornfield, 1992
 * Oreochromis niloticus vulcani (Trewavas, 1933)

The forms referred to as Oreochromis (or Tilapia) "Nyabikere" and "Kabagole" seem to belong to this species, too. An undescribed population found at, for example, Wami River, Lake Manyara and Tingaylanda seems to be a close relative.

Medical significance
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.