Fundulus luciae

Description

The spotfin killifish (Fundulus luciae) is a member of the genus Fundulus. This hardy fish is notable for spending its entire life in sporadically flooded salt marsh habitat, sheltering in shallow pools, puddles, and small tidal rivulets. It closely resembles the mummichog (Fundulus heteroclitus) in shape and coloration, but the two species can be distinguished by dorsal fin ray count: 8–9 in the spotfin versus 11–12 in the mummichog. Additionally, the dorsal fin of F. luciae originates farther back, and slightly behind the anal fin origin; in the mummichog, the dorsal fin begins anteriorly to the anal fin origin. The spotfin killifish is named for the pronounced ocellus found on the posterior dorsal fin of adult males. It is a small fish, seldom attaining 50 mm in total length. Its distribution extends along the U.S. east coast from Massachusetts to Georgia.