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Fundulus heteroclitus

The mummichog grows five to six inches long and gathers in schools of hundreds of individuals. (NOAA/Wikimedia Commons)
The mummichog grows five to six inches long and gathers in schools of hundreds of individuals. (NOAA/Wikimedia Commons)

Also known as the mud minnow, the mummichog is a minnow-like killifish found along muddy marshes, tidal creeks and the sheltered shores of the Chesapeake Bay. 


The mummichog is stout-bodied with a flattened head, rounded or squared-off tailfin, pointed teeth and a lower lip that juts out beyond the upper one. This fish grows to be five to six inches long, with females larger than males. Coloration varies with sex and shading can change based on surroundings. Females have a brownish green body featuring 12 to 15 dusky vertical stripes, with green tinted dorsal and anal fins. Males are darker than females, with a green or olive body featuring 15 silver vertical stripes. Males have yellow pectoral, pelvic and anal fins and have blue or orange markings present during spawning season. 


Muddy marshes, tidal creeks and grass flats and along sheltered shores. In summer, may range along a hundred feet of the shoreline and a few yards offshore. During colder months, often retreat to deeper waters or burrow six to eight inches deep in bottom mud or silt. 


Abundant, permanent residents of the entire Chesapeake Bay. Found on the Atlantic coast of North America from Labrador, Canada, to Mexico. 


These opportunistic feeders eat a range of items, including algae, plants, insects and insect larvae, worms, small crustaceans and mollusks, the eggs of their own species, other fish and carrion. 


Predators of mummichog include larger fish, wading birds and seabirds. 

Reproduction and Life Cycle:

Spawning occurs from April to August, during which time males often exhibit aggressive behavior. Females attract males by displaying their silvery bellies. Females can spawn up to 460 eggs eight times in a single season. Females lay sticky eggs in empty mollusk shells or on dead vegetation when the tide is highest during the new or full moon. When tide recedes, eggs are exposed to air. Eggs will not begin to hatch until once again covered with water during the next month's highest tide. When hatched, larvae measure about seven millimeters long. Most adults reach sexual maturity during their second year and live for three years. 

Other Facts:

  • "Mummichog" is a Native American word meaning "going in crowds"; mummichogs often form schools of hundreds of individuals. 
  • A tolerant species, the mummichog is able to withstand changes in temperature and salinity, low oxygen and pollution.
  • They are able to consume up to 2,000 mosquito larvae in a single day and have been introduced to ponds and ditches as natural method of mosquito control. 
  • Mummichogs are often sold to fishermen as live bait.

Sources and Additional Information:

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