Killifish and livebearers
Guppies, mollies, platies, swordtails and the killifish. 12 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, Sailfin molly, Southern platyfish, Green swordtail, Nothobranchius furzeri, Devils Hole pupfish.
Further reading
WorldAphyosemion
A large genus of small African killifish kept in home aquariums.Livebearer · Rivers and lakes
🇲🇽 Mexico and 3 moreXiphophorus
A genus of small livebearing fish native to Mexico and Central America, known for aquarium use and genetic research.Livebearer · Rivers and lakes
WorldKillifish
Small egg-laying fish known for hardiness and short lifespansLivebearer · Rivers and lakes
🇺🇸 United StatesLeast killifish
A tiny North American fish that gives birth to live young and measures just two centimetres long.Livebearer · Rivers and lakes
🇧🇷 Brazil and 1 moreLargescale four-eyes
Surface-dwelling fish with split eyes for dual vision.Livebearer · Rivers and lakes · 1758
🇲🇽 MexicoButterfly splitfin
A critically endangered livebearing fish from Mexico.Livebearer · Rivers and lakes · 1971
WorldTetra
Common name for small freshwater characiform fishes popular in aquaria.Livebearer · Rivers and lakes
Photo credits on this page
The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.
- Aphyosemion: Violaine2, CC BY 3.0, source
- Xiphophorus: Marrabbio2, CC BY-SA 3.0, source
- Killifish: TinoStrauss, CC BY-SA 3.0, source
- Least killifish: Brian Gratwicke, CC BY 2.0, source
- Mosquitofish: NOZO, CC BY-SA 3.0, source
- Largescale four-eyes: Michael Gäbler, CC BY 3.0, source
- Butterfly splitfin: Przemysław Malkowski, CC BY-SA 3.0, source
- Tetra: Holger Krisp, CC BY 3.0, source