About Killifishes and Livebearers
Small freshwater fishes including guppies, mollies, and killifishes.
Cyprinodontiformes are small fishes of freshwater and brackish habitats — killifishes (using the name broadly), livebearers (Poeciliidae: guppy, molly, platy, swordtail), and pupfishes.
Morphology. Small, often colourful; jaws may be extended. Livebearers (Poeciliidae) exhibit internal fertilization and give birth to free-swimming young, unlike most fishes that broadcast eggs.
Habitat & distribution. Warm freshwater and brackish pools, springs, and streams worldwide, with exceptional diversity in Africa and the Americas; some (pupfish) tolerate extreme deserts.
Human significance. Guppies, mollies, platies, and swordtails are among the most popular aquarium fishes; killifishes are studied for ageing and development.
