SCIENTIFIC NAME: Lucania parva
CHARACTERISTICS: The rainwater killifish has a slightly compressed body, a small, upturned mouth, and a strongly compressed caudal peduncle. Most scales are edged in black, giving them a diamond-shaped appearance. The male’s dorsal fin has a large black spot at the base, and the fin margin is orange. All other fins except the pectorals have thin black edges. The anal fin is light yellow. General body color is light yellow to straw on the back, fading to white on the venter. Small individuals are easily confused with species in the mosquitofish complex Gambusia. See Baird (1855) for original description.
ADULT SIZE: 0.8 to 2.4 in (20 to 60 mm)
DISTRIBUTION: Lucania parva is widespread from Cape Cod, Massachusetts, southward through the Atlantic and Gulf slopes to Tampico, Mexico. In Alabama, it is commonly found in fresh to brackish estuarine environments and in the Mobile Delta. Several individuals collected 92 miles upstream of the Mobile Bay in an isolated overflow pool of the lower Tombigbee River at Jackson, Clarke County, represent a new inland record for the species in Alabama (R. D. Suttkus, 1995 personal communication).
HABITAT AND BIOLOGY: Although L. parva generally prefers brackish conditions, the species is tolerant of wide-ranging salinity and consequently can be found in a variety of shallow, quiet, vegetated habitats in coastal Alabama. Hildebrand and Schroeder (1928) report ripe females from early April through July in Chesapeake Bay and speculate that spawning occurs more than once during the reproductive season. These authors also report high densities of rainwater killifish in vegetation, based on totals of 18,300 individuals in seven net hauls and 14,600 individuals in 20 net hauls. The diet of this diminutive species consists of microcrustaceans and immature aquatic insects.
ORIGINAL DESCRIPTION: Baird and Girard described the rainwater killifish in 1855.
Lucania is a coined name that Jordan left undefined in the original description.
Parva means small.
The copyrighted information above is from Fishes of Alabama and the Mobile Basin.