Oreochromis niloticus (Linnaeus, 1758)

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 795-796

Oreochromis niloticus

Common name. Nile tilapia.

Diagnosis. Distinguished from other species of Cichlidae in West Asia by: ● 3–40 dark-grey to black, regularly shaped and set vertical bars on caudal (number increasing with size) / ○ usually all flank scales with dark-grey scale pockets in preserved individuals, dark-grey scales pockets never organised in fields / ○ tip of membrane between dorsal spines black or grey / ○ chest, belly, and isthmus in front of pelvic covered by small scales / ● nuptial male whitish with pink anterior body and caudal / ○ snout not duck-bill-like elongated in male larger than 150 mm SL / ○ anterior processes of lower pharyngeal bone clearly projecting beyond anterior margin of toothed pads / ○ chest never red / ○ 19–25 gill rakers on lower part of first branchial arch / ○ 3 anal spines / ○ scales cycloid / ○ no ocelli on anal. Size up to 395 mm SL.

Distribution. Widely introduced in Oman , UAE, Saudi Arabia, and Yemen, but many might be Taiwanese red tilapia. Also introduced in North Africa, Jordan, Orontes, Iran, and Iraq. Native to Nile drainage (including Lakes Albert, Edward, and Tana), Jebel Marra, Lakes Kivu, Tanganyika, Awash, and Omo, various Ethiopian lakes, Lake Turkana, Suguta, and Lake Baringon. Also native to West Africa in Senegal, Gambia, Volta, Niger, Benue , and Chad drainages. Widespread introduction for aquaculture in other parts of Africa, Europe, and tropical countries worldwide.

Habitat. Lakes, backwaters, and slow-flowing rivers. Very common in reservoirs, canals, and other artificial water bodies. Spawns along banks in stagnant or slow-flowing water. A freshwater species that does not inhabit brackish water.

Biology. Lives up to 5 years. Matures at 3–6 months or much younger, depending on temperature and food availability. Sexually monomorphic, male larger. Spawns when temperatures exceed 20°C between April and August in North Africa. Begins spawning in February in Lake Nasser ( Egypt). Non-spawning individuals are gregarious along banks. Males form territories and dig shallow depressions in sandy or muddy shores to attract females. Nest is a circular depression up to 100 cm in diameter and 50 cm deep, usually twice length of breeding male. Males often builds their nests close together, forming leks. Females only visit nest to spawn. Courtship lasts several hours. Up to 200 eggs are laid in about 20 portions over 45–120 minutes. Eggs are picked up and placed in mouth by female as they are laid, before, during, or after fertilisation. No permanent pair bond; females incubate eggs alone while males court other females. Females may lay a full clutch with one male or several males in a series so that siblings have different fathers. Females do not feed during brood care or take small items of food, some of which are eaten in mouth by young. Water is circulated over eggs by chewing movements of female’s jaws. Females spawn several times during summer, often once a month. Females hold eggs and larvae in their

Remarks. This species is important for aquaculture worldwide and is cultivated in many countries, and escapes are expected elsewhere. Several records of O. niloticus from Türkiye are unconfirmed and all these records have been identified as O. aureus .

Further reading. Pullin & Lowe-McConnell 1982 (biology); Trewavas 1983 (description, biology). Siddiqui & Al-Harbi 1995 (hybrid tilapias in Saudi Arabia).