Killifish and livebearers
Guppies, mollies, platies, swordtails and the killifish. 25 fish on EveryFish so far.
Killifish and livebearers, the order Cyprinodontiformes, are small fish of fresh and brackish water, mostly in the Americas and Africa. The livebearers, such as guppies, mollies, platies and swordtails, give birth to free-swimming young; the males have an anal fin shaped into a mating organ. The killifish lay eggs, and some live in pools that dry out each year, their eggs surviving in the mud.
Aquarium favourites
Guppies, named after Robert Guppy, who sent specimens from Trinidad to the British Museum in the 1860s, have been bred into hundreds of colour strains and are among the most kept aquarium fish. Mollies, platies and swordtails are easy to keep and breed. Killifish are prized by specialist hobbyists for their bright colours. The turquoise killifish of Zimbabwe and Mozambique lives only a few months and is used to study ageing.
Pupfish and mosquitofish
Pupfish live in desert springs and pools of North America; the Devils Hole pupfish lives in a single water-filled cave in Nevada, the smallest range of any vertebrate. Several pupfish have gone extinct as springs were pumped dry. The mosquitofish was spread around the world, including India, to eat mosquito larvae, but it attacks native fish and frogs and is listed among the world's worst invasive species.
Famous livebearer fish
Still to be written: Guppy.
Further reading
Photo credits on this page
The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.
- Mosquitofish: NOZO, CC BY-SA 3.0, source
- Eastern mosquitofish: JeffreyGammon, CC BY-SA 4.0, source
- Sailfin molly: (c) Nick Tobler (Cowturtle), some rights reserved (CC BY), CC BY 4.0, source
- Southern platyfish: Photograph by Jere Kyyrö. Uploaded by Rasvis ., CC BY-SA 3.0, source
- Green swordtail: Bastet78, CC BY-SA 3.0, source
- Devils Hole pupfish: Olin Feuerbacher / USFWS, Public domain, source