Mummichog

The mummichog (Fundulus heteroclitus) is a small killifish found along the Atlantic coast of the United States and Canada. Also known as Atlantic killifish, mummies, gudgeons, and mud minnows, these fish inhabit brackish and coastal waters including estuaries and salt marshes. The species is noted for its hardiness and ability to tolerate highly variable salinity, temperature fluctuations from , very low oxygen levels (down to 1 mg/L), and heavily polluted ecosystems. As a result, the mummichog is a popular research subject in embryological, physiological, and toxicological studies. It is also the first fish ever sent to space, aboard Skylab in 1973.

==Taxonomy== The genus name Fundulus comes from '''', meaning bottom, from the fish's habit of swimming near muddy bottoms. The species name heteroclitus means irregular or unusual. The type specimen was first described by Carl Linnaeus in 1766, from near Charleston, South Carolina. Other scientific names now considered synonyms for this species include Cobitis heteroclita, Fundulus fasciatus, Fundulus pisculentus, and Fundulus nigrofasciatus. The mummichog belongs to the order Cyprinodontiformes, and the family Fundulidae. There are two subspecies: F. h. heteroclitus (Linnaeus, 1766), in the south and F. h. macrolepidotus (Walbaum, 1792) in the north. As F. mudfish this species was designated the type species of Fundulus when Lacépède created the genus in 1803.