Mummichog

Fundulus heteroclitus

A tough little killifish of Atlantic marshes that handles pollution and salt changes, and was the first fish in space.

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About the Mummichog

Mummichogs are about hand-sized, 5 to 7 inches long. Breeding males are olive green with bright blue or orange stripes. They live in coastal streams, estuaries and salt marshes with underwater plants, and they can move between fresh and salt water. They feed at the surface on tiny invertebrates and fish eggs, and they can eat up to 2,000 mosquito larvae a day.^[1]

Quick facts

Scientific name: Fundulus heteroclitus^[1]
Size: 5 to 7 inches long.^[1]
Lifespan: Up to 3 years in the wild.^[1]
Diet: Tiny invertebrates, mosquito larvae and fish eggs.^[1]
Habitat: Coastal streams, estuaries and salt marshes.^[1]
Group life: Dense schools of hundreds.^[1]
Babies: Up to 460 eggs at a time, laid above the water line.^[1]
Conservation status: Least Concern (IUCN Red List, assessed 2012).^[2]

Fun facts

Mummichogs were the first fish in space.^[1]
Mummichog is a Narragansett word meaning 'going in crowds.'^[1]
One mummichog can eat 2,000 mosquito larvae a day.^[1]

Vocabulary

fish: A cold-blooded animal that lives in water, breathes with gills and usually has fins and scales.
estuary: Where a river meets the sea and fresh and salt water mix.
school: A group of fish swimming together.
brackish: Slightly salty.
least concern: A conservation label meaning a species is widespread and not at risk of dying out soon.

See it in person

Smithsonian's National ZooWashington, D.C. · Bird HouseSee this animal on the zoo's website ↗

These zoos had this animal when we gathered our information, but animals sometimes move. Check the zoo's website or contact the zoo before you visit.

Sources

[1] Smithsonian's National Zoo & Conservation Biology Institute. “Mummichog.” https://nationalzoo.si.edu/animals/mummichog (accessed 2026-10-08)
[2] IUCN Red List of Threatened Species. “Fundulus heteroclitus (Mummichog).” https://www.iucnredlist.org/species/189824/18236919 (accessed 2026-10-08)

Facts last checked 2026-10-08.

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