Western Mosquitofish

Looks how to spot one

Small livebearer (relative of the guppy)

A plain grey little livebearer with rounded fins and an upturned mouth made for feeding at the surface. Females are much bigger and rounder than males and show a dark spot near the vent when carrying young; males have a modified anal fin for mating.23

Personality what they are like

A bold, quick and competitive little fish that is always ready to feed and can be pushy with tank mates.3

Grooming and care the hands-on bits

A pair can live in a tank as small as about 30 x 20 x 20 cm (12.5 litres). Because it is such a bold, competitive feeder it is best kept in a species-only tank. Import is restricted in the EU, so check local rules.32

Home where they are happiest

Still or slow, plant-rich water. Seriously Fish suggests 18-27 C, pH 6.0-8.0 and hardness 5-30 dH.31

Food basics what goes in the bowl

An omnivore that eats zooplankton, small insects and larvae and detritus; in a tank it takes most foods and enjoys live or frozen brine shrimp and Daphnia.123

Company who they like around

Breeds readily when both sexes are kept together.3

The story where it all began

Native to the Mississippi basin and Gulf coast, the mosquitofish was shipped around the world from the 1920s onward to help control mosquitoes. Today it lives on almost every continent.21

Recognised by the official bits

IUCN Red List

Least Concern (assessed 22 January 2019)1

European Union

Import restricted across the EU2