Guppy

The guppy is one of the most widely kept aquarium fish in the world. It is small, hardy, easy to feed and comes in an almost endless range of colours and fin shapes, which has made it a favourite of beginners and serious breeders alike.

Where guppies come from

Wild guppies live in streams, pools and ditches in northeast South America — Venezuela, Guyana and the islands of Trinidad and Tobago among them. They have since been released into warm waters on every continent except Antarctica, partly in the hope that they would eat mosquito larvae. The fish takes its English name from Robert John Lechmere Guppy, who sent specimens from Trinidad to the British Museum in the 1860s.

Males, females and colour

Male guppies are smaller and far more colourful than females, with long, flowing tails. Wild males already vary a lot from one to the next, and generations of selective breeding have turned that into the fancy strains seen today: solid reds and blues, snakeskin and mosaic patterns, and tails shaped like a fan (delta), a veil or a lyre. Females are larger, plainer and usually grey or olive, often with some colour in the tail.

A livebearer

Guppies do not lay eggs. The female carries the young inside her and gives birth to free-swimming fry, typically a few weeks after mating, and she can store sperm and have several broods from a single mating. A brood is often 20 to 50 fry. This is why guppies are known for breeding easily — and why an aquarium of a few guppies soon has many more. The adults will eat their own fry, so breeders give the young dense plants to hide in.

Keeping guppies

Guppies like warm, clean, slightly hard water and a tank with plants and open space to swim. Keep them in a group, ideally with more females than males, so that no single female is chased all the time. They do well with other small, peaceful fish, but long-finned males should not be kept with fin-nippers.