The Guppy, known as Poecilia reticulata, (a.k.a. the millionfish), is a small, beautiful, peaceful, lively, curious and hardy and one of the most popular freshwater aquarium fish species. It is a member of the Poeciliidae family and like all other members of the family is a live bearer. It is one of the best choices for new hobbyist, especially children.

Guppies are native to Antigua and Barbuda, Barbados, Brazil, Guyana, the Netherlands Antilles, Trinidad and Tobago, the U.S. Virgin Islands and Venezuela. However, they have been introduced to many other different countries on all continents, (except Antarctica), most often to be used as a mosquito controller, as they will readily eat mosquito larvae, slowing the spread of malaria. But they were also introduced by accident. In most cases, the guppies have had a negative impact on native fish faunas.