花鳉科是辐鳍鱼纲鲤齿目中的一个科，它包含200多个种和亚种。

花鳉科中的鱼都比较小，大多数生活在淡水中，只有少数几种生活在咸水中。最大的花鳉科的鱼是墨西哥魣鳉（Belonesox belizanus），只达15厘米，一般花鳉科的鱼只到10厘米。这些鱼有两个经济价值：首先它们是很好的控制蚊子的生物，其次它们是比较顽强的，色彩鲜艳的观赏鱼。作为控制蚊虫的生物它们从它们在美洲的热带和亚热带家乡被人类移居到几乎所有的地区。花鳉科本来只在美洲大陆上出现说明这个科是一个比较新的科，是在美洲大陆与其它大陆分隔后才形成的。

Poeciliidae is a family of freshwater fishes of the order Cyprinodontiformes, the tooth-carps, and include well-known live-bearing aquarium fish, such as the guppy, molly, platy, and swordtail. The original distribution of the family was the southeastern United States to north of Rio de la Plata, Argentina, and Africa, including Madagascar. However, due to release of aquarium specimens and the widespread use of species of the genera Poecilia and Gambusia for mosquito control, poeciliids can today be found in all tropical and subtropical areas of the world. In addition, Poecilia and Gambusia specimens have been identified in hot springs pools as far north as Banff, Alberta.