Actinopteri (ray-finned fishes) > Cichliformes
(Cichlids, convict blennies) > Cichlidae
(Cichlids) > Pseudocrenilabrinae
Etymology: Oreochromis: Latin, aurum = gold + Greek, chromis = a fish, perhaps a perch (Ref. 45335); aureus: From the Greek words oreos=of the mountains and chroma=color; aureus (Latin)=golden from aurum, gold (Ref. 79012). More on author: Steindachner.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; brackish; benthopelagic; potamodromous (Ref. 51243); depth range 5 - ? m. Tropical; 8°C - 30°C (Ref. 2); 35°N - 10°N
Africa and Eurasia: Jordan Valley, Lower Nile, Chad Basin, Benue, middle and upper Niger, Senegal River (Ref. 21). Introduced in the oasis of Azraq (Jordan) as well as in warm water ponds of USA, South and Central America and South East Asia. At least one country reports adverse ecological impact after introduction.
Length at first maturity / Size / Weight / Age
Maturity: Lm ?, range 13 - 20 cm
Max length : 45.7 cm TL male/unsexed; (Ref. 40637); common length : 16.0 cm TL male/unsexed; (Ref. 12193); max. published weight: 2.0 kg (Ref. 40637)
(total): 14 - 17;
soft rays: 8 - 11;
Vertebrae: 28 - 31. Diagnosis: Adults: narrow preorbital bone (depth max. 21.5% of head length in fishes up to 21.3cm SL); lower pharyngeal jaw with short blade; no enlargement of the jaws in mature fish (lower jaw not exceeding and usually less than 36.8% head length) (Ref. 2). Caudal without regular dark vertical stripes (Ref. 2, 53405, 54467), but with a broad pink to bright red distal margin (Ref. 2). Breeding males assume an intense bright metallic blue on the head, a vermilion edge to the dorsal fin and a more intense pink on the caudal margin (Ref. 2, 54467). Breeding females with the edges of dorsal and caudal fins in a paler more orange color (Ref. 2). Juveniles: upper line of head profile running upward from snout at sharp angle; lower pharyngeal bone nearly triangular, teeth numerous but not densely crowded; dorsal and anal fin striped, with stripes running obliquely on the soft dorsal and longitudinally on the caudal fin; black Tilapia-mark on soft dorsal present; body dark; lower lip developed from beneath (Ref. 54566).
Cold tolerant (Ref. 23, 61, 55352), occuring at temperatures ranging from 8°-30°C (Ref. 2), tolerating up to 41 °C (Ref. 23). Tolerates fairly brackish conditions (Ref. 3, 23, 61, 2001, 6465, 54362). Forms schools; is sometimes territorial; inhabits warm ponds and impoundments as well as lakes and streams (Ref. 5723, 11028), in open water as well as among stones and vegetation (Ref. 11028). Feeds on phytoplankton and small quantities of zooplankton (Ref. 3, 61, 6465, 52307). Young fish have a more varied diet which includes large quantities of copepods and cladocerans (Ref. 2, 61, 6465), but they also take pieces of small invertebrates (Ref. 52307). Ovophilic, agamous (Ref. 52307), maternal mouthbrooder (Ref. 364, 52307). Sexual maturity in ponds reached at age of 5-6 months (Ref. 55352). Reproduces in both fresh and brackish water (Ref. 61, 5723). Good taste (Ref. 61).
Nesting usually in shallow water weedy areas (Ref. 96). Males establish territory and dig a spawning pit (Ref. 2, 6465, 54601), using mouth and fins (Ref. 2), up to 60cm deep and 4-6m in diameter; a number of territories can often be found clustered together (Ref. 52307). Territories are defended by means of agressive behaviour (Ref. 6465), including lateral display, lateral biting and mouth-to-mouth combat (Ref. 2). Reproduction is stimulated by long photoperiods and inhibited by short daylengths (Ref. 54365). Reproduction requires a minimum temperature of about 20°C (Ref. 2). Males visit schools of females and attempt to attract a female spawning partner (Ref. 2, 52307). Courting behaviour in the nest consists of lateral display by both sexes with nipping and tail-flapping (Ref. 2). Eggs are deposited in single clutches, from several dozen to 100 eggs (Ref. 52307), and are taken into the females mouth as soon as they are fertilized (Ref. 2, 6465, 52307), with a peak spawning frequency around the 9-11th hour of light (Ref. 31140, 54365). One female may hold up to 2000 eggs in her mouth (Ref. 2). The female swims away to deeper water with the brood after spawning is complete (Ref. 2, 52307), while the male renews spawning activities with another female. Hatching occurs about 3 days after oviposition (Ref. 2). Incubation time varies with temperature, 13-14 days at 25-27°C (Ref. 2, 52307) or 8-10 days at 29°C (Ref. 144), and juveniles leave the mother's mouth when they are about 1.1cm in length (Ref. 54601). The young school near parent's head for a few days, reentering the mouth at any sign of danger or at a gesture of the female; parent-offspring relationship ceases after 5 days (Ref. 2).
Trewavas, E., 1983. Tilapiine fishes of the genera Sarotherodon, Oreochromis and Danakilia. British Mus. Nat. Hist., London, UK. 583 p. (Ref. 2)
IUCN Red List Status (Ref. 123251)
CITES (Ref. 123416)
Threat to humans
Potential pest (Ref. 6465)
Fisheries: highly commercial; aquaculture: commercial; aquarium: commercial; bait: usually
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01905 (0.01473 - 0.02466), b=2.98 (2.94 - 3.02), in cm total length, based on LWR estimates for this species (Ref. 93245
Trophic level (Ref. 69278
): 2.1 ±0.0 se; based on diet studies.
Resilience (Ref. 120179
): High, minimum population doubling time less than 15 months (K=0.48-0.58; tm<1).
Vulnerability (Ref. 59153
): Low to moderate vulnerability (27 of 100) .