Guppy

The guppy, Poecilia reticulata, is a small livebearing fish native to streams, ditches, and lowland waters of northeastern South America and nearby Caribbean islands, especially Trinidad and Tobago. Wild males are slender and brightly marked, while females are larger, plainer, and capable of giving birth to free-swimming fry rather than laying eggs. Aquarium strains have been selected for fan, delta, sword, and ribbon tails, along with countless colors and patterns. Fancy guppies, feeder guppies, and wild-type or locality guppies can differ greatly in hardiness and body shape.

Guppies are often recommended as beginner fish, but they still need a cycled aquarium, stable warm water, and protection from fin-nipping or predatory tankmates. They usually thrive in moderately hard, slightly alkaline water and appreciate plants or floating cover where fry can hide. Because females store sperm, a single purchased female may produce several broods, making population control part of routine care. Line breeding for show traits requires separate tanks and careful culling, while keepers preserving wild or locality strains should avoid mixing them with fancy stock. A varied diet of quality flake, small frozen foods, and vegetable matter suits their omnivorous feeding.