Western Mosquitofish (Gambusia affinis)

From The Aquarium Wiki
Jump to: navigation, search

Western Mosquitofish

Female Western Mosquitofish

Gambusia affinis

38 Litres (10 US G.)

2.5-5.1cm (1-2 ")


1 - 1.015


6.0 - 8.0

12 -29 °C (53.6-84.2°F)

5-19 °d

1:2 M:F

Pellet Foods
Flake Foods
Live Foods

3-5 years



This animal is available captive bred

Additional names

Mosquito Fish, Western Mosquitofish

Additional scientific names

Heterandria affinis, Gambusia affinis affinis, Gambusia gracilis


Found across North and Central America, primarily in the Mississippi River basin from central Indiana and Illinois in USA south to Gulf of Mexico and Gulf Slope drainages west to Mexico. Has also been introduced elsewhere, with some damage to native species.


Females are larger than males, and dull in colour. Males have some colour, which distinguishes them from females. Males also have a gonopodium, used in breeding rituals in which the males will 'display' for the females.


See our article on Breeding Gambusia affinis.

Tank compatibility[edit]

Aggressive fin nippers, are best with hardy sub-tropical fish such as Rosy Reds and White Cloud Mountain Minnows. Very easy to breed and will multiply in an aquarium. Like Guppies, keep in a ratio of one male per two-three females.


Good foods would be brine shrimp, bloodworms and daphnia, supplemented with flakes. Also will eat some plants.

Feeding regime[edit]

Mosquito Fish should be fed twice a day maximum, once every other day minimum.

Environment specifics[edit]

Slightly brackish water can help the fish's health. The tank should be spacious with hiding places in planting (plants including Java Fern will tolerate a brackish environment and are unlikely to be eaten), rocks and bogwood.


Females are more aggressive towards males, so male to female ratio should be 1:3. They will nip at other fish, so they should be kept with the same species.


Not a colourful fish, they have translucent fins with faint dark speckling and pale green/yellow/cream bodies, female Mosquito Fish and female Guppies look a lot alike. Males have blue iridescence on their flanks.


External links[edit]