Poeciliidae, Bonaparte, 1831

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 763-766

Family Poeciliidae

Livebearers elsewhere. Guppies and mosquitofish Gambusia holbrooki are typically introduced to control mosquito populations. A large family of small, fresh- and brackish-water fishes dis- However, global studies have demonstrated that these introtributed across the Americas, from southern USA to Argen- ductions have had only limited effects on mosquito numbers, tina. The majority of species exhibit internal fertilisation with potentially negative or neutral impacts on native fish and give birth to live young. They also exhibit striking sexual populations. There needs to be a clear justification for these dimorphism, with females being larger and deeper-bodied introduction programs, which are ongoing in some countries. than males. The male’s anal is modified into an intromittent It has been demonstrated that mosquitofish is the main or organ (gonopodium) ( Fig. 65) through which sperm is intro- one of the main causes of the critical decline or extirpation of duced into the female’s body. Females store sperm, which can several populations of species of Aphaniids and other fishes.

be used to fertilise several successive broods. The eyes of the In West Asia, only Gambusia holbrooki is widespread. embryos are occasionally visible in a blackish blotch through In addition to the species discussed here, other introduced the female’s belly, immediately in front of and above the anal. poecilids may be present, particularly in and around cities. One species, guppy Poecilia reticulata , is one of the world’s Specialist aquarium literature will allow theiridentification. most popular aquarium fishes and has been released through- Further reading. Meyer et al. 1985; Meffe & Snelson 1989; out the tropics and in various kinds of warm-water habitats Miller 2005; Freyhof et al. 2020 (introductions in Arabia).

Key to species of Poeciliidae in West Asia 1a - Male with long, sword-like prolongation of lower caudal, both sexes with a prominent, red, black, or green midlateral stripe. ……………… Xiphophorus hellerii 1b - Male without prolongation of caudal, without prominent midlateral stripe. ………………2 2a - Pelvic of male unmodified, tip of first ray not enlarged, similar in male and female in size and shape;gonopodium long. ……………… Gambusia holbrooki 2b - Pelvic of male modified, tip of first ray enlarged, different in male and female; gonopodium short. ………………3 3a - Body very short and deep; dorsal in male and female equal; flank often red, similar colour in both sexes. ……………… Xiphophorus maculatus 3b - Body moderately elongate, without grey blotch on posterior part of caudal peduncle; dorsal larger in male than in female; flank not red, if with red blotches, then in male only. ………………4 4a - Dorsal and caudal in male with blue, white, or red colour; flank in male with a variable colour pattern of red, turquoise, yellow, and black blotches and short stripes. ……………… Poecilia reticulata 4b - Both sexes with rows of small black, grey, or brown spots on flank or flank black or black mottled; male without coloured blotches or stripes. ………………5 5a - Dorsal origin above or in front of anal origin; 12–16½ dorsal rays in male forming a large sail. ……………… Poecilia “ latipinna ” 5b - Dorsal origin behind vertical of pelvic origin in male; usually 9½ dorsal rays in male, rays slightly prolonged. ……………… Poecilia “ shenops ”

Open Access. © 2025 JÖrg Freyhof, Baran Yoğurtçuoğlu, Arash Jouladeh-Roudbar and Cüneyt Kaya, published by De Gruyter. the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

https://doi.org/10.1515/9783111677811-039

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Gambusia holbrooki ; Lower Seyhan; female, 40 mm SL.

Gambusia holbrooki ; Lower Tarsus, Türkiye; ~ 18 mm SL.

Gambusia holbrooki it would control mosquitoes (vectors of various diseases). Common name. Eastern mosquitofish. There is no evidence that it has had any effect on mosquito

Diagnosis. Distinguished from other species of Poeciliidae populations, but there is increasing evidence that it impacts in West Asia by: ● pelvic of male unmodified, tip of first ray native fish, seriously threatening many endemic species. not enlarged, similar in male and female / ● gonopodium Remarks. Often referred to as G. affinis , a species identilong ● male dull grey / ● both sexes with rows of black spots fied by details of gonopodium morphology, 5½ dorsal rays in dorsal and caudal / ○ dorsal and caudal with black spots (vs. 6½ in G. holbrooki ) and 8½ anal rays (vs. 9½). There are / ○ no blue or red blotches on flank in male / ○ dorsal origin no confirmed records of G. affinis from West Asia. After the far behind vertical of anal origin / ○ no lateral stripe / ○ initial import in 1921, most subsequent introductions into male without sword-like prolongation on caudal. Size up to Europe, North Africa, and West Asia were from European 30 mm SL in male, 55 mm in female. stocks. Still, Gambusia was also imported and introduced

Distribution. Introduced throughout warmer parts of after 1921; at least one import was from the native range of West Asia, North Africa, and southern Europe. Throughout G. affinis . Introduced populations in China are all G. affinis . Mediterranean basin, including Nile and Cyprus. Locally Furtherreading. Wootenetal.1988(genetics);Rauchenberger in southern Caspian basin and coastal areas of Black Sea 1989 (phylogeny); Jenkins & Burkhead 1993 (biology); basin. Iran and locally in Saudi Arabia (Al-Ahsa oasis, Lake Doadrio 2001; Yoğurtçuoğlu & Ekmekçi 2017 (biology); Alsfar, wadis around Riyadh). Native to North America, Kurtul 2018 (biology and ecology); Kurtul & Sarı 2017 (risk from Delaware drainage to Florida and Alabama. potential); Kurtul & Sarı 2019 (distribution in Türkiye);

Habitat. Still or slow-flowing waters, usually with dense Kurtul & Sarı 2020 (biology); Kurtul & Sarı 2021 (recognition aquatic vegetation. Can survive in heavily polluted waters level); Freyhof et al. 2020 (distribution in Saudi Arabia).

by absorbing oxygen from top surface layers. Often, last

fish survive in heavily polluted streams.

Biology. Matures at 4–6 weeks, three or more generations

can be produced in a year. Breeds from April–October

(depending on latitude), all year in south. Gestation lasts

3–4 weeks. Brood can be up to 354 young, usually between

40 and 60. Sexual activity ceases when temperatures drop

below 18°C. While females continue to grow throughout

their lives, males stop growing when they reach repro-

ductive size. Feeds mainly on small aquatic invertebrates,

highly opportunistic depending on prey availability. Lives

below surface, catching prey at or just below surface.

Conservation status. Non-native; first introduced to

Europe in Spain (1921) by health authorities in hope that

Released aquarium fishes: A looming danger? The aquarium trade represents a significant pathway for introducing non-native species worldwide, including those in West Asia. All Poeciliid species introduced, except G. holbrooki , originate from aquarium populations released to the wild. Additionally, Amatitlania nigrofasciata , Carassius auratus , Clarias sp. , and Pterygoplichthys catfish have been released from aquaria and established in the wild. The dilemma faced by aquarium fish owners is evident. What should they do with the fish if they no longer wish to keep the aquarium or particular fish? Usually, these fish cannot be returned to the shop or given to other hobbyists. The fish owner is unlikely to want to kill them, so they are often released into the wild. While many hundreds of fish species are kept in aquaria, only a small number can survive and establish themselves in the waters of West Asia. Most aquarium fishes are adapted to tropical conditions and fail to survive cold winters. This is why warm springs are often where released aquarium fishes can be found. Many species are domesticated or originate from tropical rainforest habitats, making it difficult for them to establish in local fish communities. Nevertheless, numerous species are potentially able to cope with the conditions in West Asia, particularly those originating from Europe, North America, and China. Fortunately, these species are less popular in the aquarium trade. Non-native species such as Atractosteus spatula , Pangasianodon hypophthalmus , Piaractus brachypomus , and Labeo rohita are not only sourced from the aquarium trade but also originate from escapees from aquaculture facilities.

Poecilia “ latipinna ”; Hasan Abad, Iran; female, 61 mm SL.

Poecilia “ latipinna ”; Israel; male, ~ 50 mm SL. © M. Ford.