Poecilia reticulata, Peters, 1859

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 768-770

Poecilia reticulata

Common name. Guppy.

Diagnosis. Distinguished from other species of Poeciliidae in West Asia by: ● male brightly coloured in life, with black blotches on flank also seen in preserved individuals / ○ dorsal and caudal in male with blue, white or red colour / ○ flank in male with a variable colour pattern of red, turquoise, yellow, orange, and black blotches and short stripes / ○ dorsal larger in male than in female / ○ flank not red, if with red blotches, then in male only / ○ pelvic of male modified, tip of first ray enlarged, different in male and female / ○ body moderately elongate / ○ dorsal origin behind vertical of anal origin / ○ gonopodium short / ○ dorsal and caudal without black spots / ○ no lateral stripe / ○ male without sword-like prolongation on caudal. Size up to 35 mm SL in male 50 mm SL in female.

Distribution. Introduced worldwide. Established in warm springs in upper Sakarya, İzmir, and upper Tohma drainages (Euphrates, Türkiye). Likely established elsewhere in West Asia. Also locally established in hot springs in Europe and in warm effluents from European power stations. Native to Venezuela, Guyana, and adjacent islands.

Habitat. A wide variety of habitats with low predation pressure. Usually found in very small streams and densely vegetated lakes and springs.

Biology. Not studied in West Asian populations. In captive populations, females mature at about 3 months, males slightly earlier. Continuous, non-resource and non-territorial mating system. Sexually dimorphic. Males brightly coloured and highly polymorphic with many cultivated colour forms; females cryptically coloured. Predation is a major evolutionary pressure influencing colouration, life history traits, and behaviour. Widely used as a model in biology, especially to study evolution.

Remarks. Despite being one of the most common aquarium fish in the world, there are few confirmed records of guppies being introduced in West Asia, with some populations surviving for more than 40 years. Poecilia wingei and P. obscura are two other guppies kept in the hobby, and hybrids between P. wingei and P. reticulata are particularly common and likely to be released into the wild. Although we identify all wild guppy populations as P. reticulata , this is likely incorrect. Hybrid populations with P. wingei are likely to occur, especially in more recently established populations. Conservation status. Non-native; released from aquaria.

Further reading. Haskins et al. 1961 (ecology); Liley & Seghers 1975 (behaviour); Reznick et al. 1990 (biology); Magurran et al. 1995 (behaviour); Houde 1997 (reproduction); Esmaeili et al. 2017 (introduction in Iran); Freyhof et al. 2020 (distribution in Arabia).

Poecilia sphenops ; Ruwayyah, Dubai, UAE; male, 35 mm SL.© J. Els.

Poecilia “sphenops ” Province of Saudi Arabia, including Al-Ahsa oasis, adja- Common name. Mexican molly. cent to Lake Alsfar, and coastal wetlands at Salwar, north Diagnosis. Character states often intermediate between of Qatif and south of Jubail. Also established in UAE for this “species” and P. “ latipinna ”. Distinguished from other 40 years or more in Ruwayyah, a traditional plantation species of Poeciliidae in West Asia by: ● usually 9½ dorsal area inland from urban Dubai. Also, present on a recently rays in male, not forming a sail / ● dorsal origin behind ver- developed golf course on outskirts of Dubai. Poecilia tical of pelvic origin / ○ both sexes with rows of small black, sphenops is native to Central America, from Mexico to grey or brown spots on flank or flank black or black mottled Guatemala. Widespread in tropical areas through aquar- / ○ male without coloured blotches or stripes / ○ dorsal larger ium releases.

in male than in female / ○ flank not red / ○ pelvic of male Habitat. Euryhaline, but usually in slightly brackish waters modified, tip of first ray enlarged, different in male and and lower parts of rivers, lagoons, marshes, and streams.

female / ○ gonopodium short / ○ body moderately elongate / Biology. Matures in less than a year. Produces up to 150 ○ no lateral stripe / ○ male without sword-like prolongation young after a gestation period of about 28 days. Females give on caudal. Size up to 75 mm SL. birth throughout year in warm waters. Feeds on algae and Distribution. Hybrids identified as this species are locally small invertebrates. Black variety (Black Molly) is a popular established in Israel and Italy, at several sites in Eastern aquarium fish and is marketed throughout the world.

Xiphophorus hellerii ; Euphrates drainage, Türkiye; female, ~ 35 mm SL. Xiphophorus hellerii ; Euphrates drainage, Türkiye; primary male, ~ 35 mm SL.

Xiphophorus hellerii ; Euphrates drainage, Türkiye; secondary male, ~ 35 mm SL.

Conservation status. Non-native; released from aquaria.

Remarks. Non-native mollies are incorrectly identified as P. sphenops . See notes under P. “ latipinna ”. In the UAE, this molly occurs in two colour variants: pale beige and black beige mottled. In its native range, several species appear to be included in P.sphenops , further complicating thesituation. Further reading. Miller 2005 (distribution, identification); Freyhof et al. 2020 (distribution in Arabia).