Bony fish · Cyprinodontiformes · Fundulidae

Mummichog

Fundulus heteroclitus

Least Concern

The species is abundant and widely distributed; it faces no significant short-term risk. See full glossary

A small fish of the saltmarshes of the Atlantic coast of North America, stocky and olive with pale mottling. It lives in tidal pools where temperature, oxygen and salinity change drastically every day, and tolerates those swings better than almost any other vertebrate.

Size

7 cm – 15 cm

Lifespan

4 years

Diet

Omnivore

Combines animal and plant food depending on availability.

Social structure

Colony

Lives in large concentrations, often for breeding reasons.

Sighting difficulty

Easy

OceanOmnivore Colonial Fish Ocean

6countries 10parks

Fun facts

It withstands salinities from fresh water to twice that of the sea, and temperature swings of more than thirty degrees over the year.
Populations living in heavily polluted industrial estuaries have developed, within a few decades, genetic resistance to toxic compounds that would kill individuals from clean areas — one of the best-documented cases of rapid evolution in a vertebrate.
It travelled into space on the Skylab 3 mission in 1973 to study how fish orient themselves in the absence of gravity.
It is one of the most tolerant vertebrates in existence: it withstands extreme changes in salinity, temperature and oxygen, which has made it a classic model in comparative physiology.
It was the first fish to travel into space: specimens were taken up on the Skylab programme in 1973 to study how they orient themselves without gravity.
Some populations in heavily polluted estuaries have evolved genetic resistance to PCBs and dioxins within a few decades. It is one of the best-documented cases of rapid evolution in response to pollution.
That resistance arose independently in several different estuaries, from genetic variants that were already present in the population.
It is called the mummichog, a name of Algonquian origin that means roughly 'they go in crowds'.

Life cycle & biology

Skeleton type: Vertebrate - internal bony skeleton (fish)
Habitat & environment: Brackish marshes, creeks and tidal pools of the Atlantic coast of North America

Sources consulted: https://es.wikipedia.org/wiki/Fundulus_heteroclitus