Western Mosquitofish
Gambusia affinis
The Western Mosquitofish (Gambusia affinis) is a peaceful fish that's rewarding to keep. Give it a tank of at least 25 litres (7 US gallons), water held at 64-81°F, and a pH of 6.5-7.5.
Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
North America
- Central America & Mexico
Regional colours match the stocking calculator's origin map.
Western Mosquitofish Tank Setup
A tank of at least 25 litres (7 US gallons) works well. Keep the water at 64-81°F with a pH around 6.5-7.5, and set up both cover and open swimming space where they spend most of their time (Mid).
What Do Western Mosquitofish Eat?
They're not fussy eaters - feed a varied diet, rotating good-quality dry, frozen, and gel foods rather than the same thing every day, and match the food size to their mouths.
Western Mosquitofish Tank Mates
The Western Mosquitofish is peaceful, which is the first thing to weigh up when you choose tank mates. Good matches come down to the whole stocking list working together - temperature, tank size, and temperament - not any single label. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.
Are Western Mosquitofish Good for Beginners?
Care demand varies by line and setup. Match the care level to how often you actually test and change water.
Western Mosquitofish - frequently asked questions
What size tank do Western Mosquitofish need?
Western Mosquitofish need a tank of at least 25 litres (7 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.
What water parameters do Western Mosquitofish need?
Keep them at 64-81°F with a pH of 6.5-7.5, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.
What do Western Mosquitofish eat?
Western Mosquitofish are omnivores and aren't fussy eaters. Feed a varied mix of good-quality dry, frozen, and gel foods, and match the food size to their mouths. Feed small amounts once or twice a day, and remove anything they don't eat.
Are Western Mosquitofish good for beginners?
It depends on the setup. Match Western Mosquitofish to how often you actually test water and perform maintenance.
Building a community? Run the full list through the stocking calculator before you add anything else.
Great tank mates
Chosen from temperament, overlapping temperature/pH bands, plausible minimum tank footprints, and size versus yours in App-aquatic data. Hobby nuance always wins - verify stocking and temperament before purchasing.
Fish to avoid mixing with Western Mosquitofish
These well-known species are commonly sold alongside this fish but are not recommended tank mates - verify before purchasing.
- OscarPredator - Oscar will eat or injure smaller tank mates
- AxolotlPredator - Axolotl will eat or injure smaller tank mates
- Betta (Male)Predator - Betta (Male) will eat or injure smaller tank mates
