Coptodon zillii, Both

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 784

Coptodon zillii

Common name. Redbelly tilapia.

Diagnosis. Distinguished from other species of Cichlidae in West Asia by: ● chest red or red and black in adults, red colour restricted to lateral chest in juveniles (rarely absent) / ○ lower jaw not projecting / ○ caudal with tessellate pattern / ○ chest, belly, and isthmus in front of pelvic covered by small scales / ○ 8–11 gill rakers on lower part of first branchial arch / ○ 3 anal spines / ○ scales cycloid / ○ no ocelli on anal. Size up to 400 mm SL, usually about 200 mm SL.

Distribution . In West Asia, native to Jordan drainage and possibly a few adjacent coastal streams. Introduced in Köy- ceğiz and Burdur basins in Türkiye; Euphrates and Tigris in Syria, Iraq, and Iran; Azraq oasis in Jordan; and Ceyhan and Orontes drainage in Syria and Türkiye. Also native to Nile drainage and Lakes Albert and Turkana. Widespread in West Africa, including Senegal, Gambia, Niger, Chad, and Volta, and many coastal rivers in Ivory Coast and between Volta and Niger. Occurs in Ubangui, Ulele, and Ituri in central Congo basin. Morocco: Lower valley of Oued Dr’aa and Oued Aouedri, a small Saharan valley between Tan Tan and Tarfaya. Algeria: Tolga, Zibans, and Touggourt oases in northern Sahara and on western slopes of Ahaggar, in Tassili n’ Ajjer, and Arak, a tributary of Botha, all in southern Alge- rian Sahara. Tunisia: Kebili oasis and perhaps more widely in eastern and southern Chott el Djerid basin. In Sahara: Tibesti, Ennedi, and Borkou mountains. Introduced almost everywhere in subtropical and tropical areas of Southeast Asia, Australia, India, Madagascar, New Caledonia, Fiji, Guam, Taiwan, China, Philippines, Japan, Antigua, Mexico, and the USA, including Hawaii and elsewhere.

Habitat. Hypersaline desert ponds and wadis to small rain- forest streams with soft and acidic water. Often very abun- dant in standing water, such as lakes, large rivers, or reser- voirs with dense riparian vegetation.

Biology. Usually lives 3–5 years. Matures at about 80 mm SL. Growth extremely variable depending on tempera- ture and food availability; may spawn after a year in West Asia but mature within 4 months in tropics. Forms pairs that defend territories against other fish. Usually, females defend a smaller inner territory and males a larger outer territory around spawning site. Females lay sticky eggs on surfaces such as stones or wood, often in shelters or small depressions in substrate dug by both parents. Spawns throughout year in tropical range, late spring to summer in West Asia when water temperatures rise above 20°C. Stops spawning when water temperature rises above 28°C. Both parents fan eggs, picking up debris and dead eggs. Larvae usually hatch 48 hours after spawning (25°C) and are trans- ferred to small burrows in substrate or under wood or stones. Larvae begin to feed about a week after spawning. Both parents guard larvae and juveniles for about 4 weeks. Survives temperatures as low as 6.5 and as high as 42.5°C, but only briefly, unable to survive below 10°C for more than a few hours. Harsh winters cause mortality in northern part of range. Survives in salinities up to 45 ‰ and repro- duces in salinities up to 29 ‰. Feeds mainly on aquatic and terrestrial macrophytes but also on invertebrates, algae, detritus, and virtually all organic matter. Of great economic importance in sub-Saharan Africa as a food fish for smallscale fisheries, rarely used in aquaculture. Introduced for aquatic weed and mosquito control, as forage or food fish, and for aquaculture. Several studies show negative impacts on native biodiversity, adverse effects on aquatic plants, and it is a pest in rice plantations.

Conservation status. LC.

Remarks. Populations of C. zillii from Morocco, Algeria, West Africa, the Nile, and Jordan are almost identical in their mitochondrial DNA, suggesting a very recent inva- sion of this species into the Levant and a recent interruption of gene flow between the Niger, Senegal, Nile, and many coastal rivers in West Africa. Locally misidentified as C. rendalli in 20 th century.

Further reading. Geiger et al. 2014 (molecular diversity); Nico et al. 2016 (distribution, effects of non-native populations).

Figures

Coptodon zillii

Distribution