Species: Fundulus heteroclitus, Mummichog Killifish

Fundulus heteroclitus (Linnaeus, 1766)

Mummichog Killifish

Body elongate, depth < 1/3 SL, compressed at rear; head flattened above, snout round, short; front nostril not tubular; cover of eye not continuous with head skin; mouth level with or slightly above mid-eye level, small, opens at front, oblique, protrusible, lower jaw projecting; top jaw twisted, not straight; lower jaw with 8 pores; jaws with multi-serial teeth, outer series conical; 9-11 (8-15) gill rakers; no spines in fins; dorsal fin 11-12 (10-15) short based, origin distinctly before anal fin, especially in males, with same or more rays than anal fin; anal fin with 3rd fin ray branched, 10-11 (9-14); tail fin rounded; pectoral 15-21 with narrow base, rounded, inserted low on side; pelvics inserted well behind pectoral base; small (31-34 along midside) smooth scales; lateral line reduced to a series of pits along side of body.

Female plain; no ocellus or dark blotch on dorsal fin; male body with dark and silvery vertical bars, with silver dots on pale bars, dark bars usually wider than or equal to interspaces; no thin dark line under eye or on opercle; an ocellus at the rear insertion of the dorsal fin.

Reaches 18 cm TL

Habitat: tidal creeks and marshes; marine, brackish and freshwater salinities

Depth range 0-5 m

Gulf of St Lawrence to mid east coast of Florida, and Bermuda

Note: Fundulus relictus and F. bermudae from Bermuda are synonyms