Live Vertebrates >> Fish >> Guppies

The guppy, also known as guppie (Poecilia reticulata) is one of the most popular freshwater aquarium fish species in the world. It is a small member of the Poecilidae family (females 3 centimetres long, males 2 centimetres long) and like all other members of the family, is live-bearing. It prefers a hard water aquarium and can withstand levels of salinity up to 150% sea water (58 ppt sodium chloride), which has led to them being occasional included in marine tropical community tanks, as well as more usually in freshwater tropical tanks. Its most famous characteristic is its propensity for breeding.

In its natural environment in South America and the Caribbean, guppies are often found as isolated breeding populations. In its native range, the guppy can be found in small streams and ponds of virtually any size. In Trinidad they are colloquially known as "millions" because of their fecundity.

In many countries with tropical, subtropical and mediterranean climates where guppies were not originally present, they have escaped from captivity and established naturally breeding ("feral") populations. It has also been introduced to some areas to keep down the mosquito population and help fight malaria, usually with mixed or negative results to the local ecosystem.