- Size: less than 5” long.
- Color: males dark green or steel blue above with yellow and white spots, light bellies, and silvery bars on sides (color intensifies in breeding season); females are olive green.
- Habitat: Spartina salt marshes.
- When and where to observe: most likely to see from spring to fall in salt marshes like Idlewild Preserve and Marine Park.
Just like it’s hometown, the Killifish is a tough New Yorker. Also called the common Mummichog, this fish withstands not only polluted waters, but also low oxygen levels, high salinity, and temperature shifts. Not bad for a critter less than 5” long!
Found along the Atlantic coast to the Gulf of Mexico, Killifish are omnivores, eating plants, animals, and even dead fish. They help terrestrial New Yorkers by consuming huge amounts of mosquito larvae.
Males are dark green or steel blue with a yellow and white spotting pattern above, while their bellies are white, pale yellow or orange. Silvery bars decorate their sides. Colorful as this may already sound, their color intensifies in breeding season. Females are always in olive green with lighter undersides.
Besides the vibrant colors in breeding season, males fight with each other as they vie for the attention of females. Killifish spawn (reproduce) up to eight times between spring and fall. Females may lay over 400 pale yellow eggs in a few inches of water in shady spots, and eggs hatch in 9-18 days, depending on temperatures.
Young Killifish coloring varies from pale to dark with dark bars on the sides that disappear as they mature.
As cooler temperatures begin in fall and winter, most Killifish burrow into the mud up to 6-8” deep. Their burrowing technique also helps them if they become stranded in tiny pools of evaporating water.
Visit these tough little fish in the Spartina salt marshes all around New York like those found at Idlewild Preserve or Marine Park’s Salt Marsh Environmental Center.
- Common Mummichog by the Gulf of Maine Research Institute, accessed on April 1, 2009 at http://www.gma.org/fogm/Fundulus_heteroclitus.htm.
- Wild New York: A Guide to the Wildlife, Wild Places and Natural Phenomena of New York City by Margaret Mittelbach and Michael Crewdson, published 1997 by Three Rivers Press.
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