guppy

The guppy (Poecilia reticulata) is a small freshwater fish in the family Poeciliidae. It is native to the Caribbean drainages of northeast South America, including Trinidad and Guyana, and has been widely introduced around the world as an ornamental and educational species.

Adults grow to about 2.5 to 6 cm in length. Males are typically more colorful with larger, elaborate tail fins, while females are larger and less ornate. Color patterns and fin shapes vary extensively due to selective breeding in the aquarium hobby, resulting in a wide range of strains and appearances.

They inhabit warm, slow-moving or standing freshwater with vegetation. Guppies are omnivorous, feeding on small invertebrates, algae, and prepared aquarium foods.

Guppies are livebearers. Males use a modified anal fin (gonopodium) to inseminate females internally. Gestation lasts about 21–30 days, with females giving birth to roughly 20–100 fry, depending on conditions. Fry mature quickly and can become breeding adults within a few months.

In aquaria, guppies are known for hardiness and adaptability to a range of water conditions and foods. They breed readily, which can lead to rapid population growth; many keep separate sexes or remove fry to manage numbers.

Ecologically, released aquarium populations can become established in suitable habitats and may impact native species. The guppy has also served as a model organism in genetic and evolutionary studies due to its diverse coloration and reproductive traits.