Guppies

Fish - Fresh Water

The guppy (Poecilia reticulata), also known as the millionfish, is one of the most popular freshwater aquarium fish species in the world. It is a small member of the Poeciliidae family [females 4–6 centimetres (1.6–2.4 in) long, males 2.5–3.5 centimetres (1.0–1.4 in) long] and like all other members of the family, is live-bearing.

http://en.wikipedia.org/wiki/Guppy