SPRINGS FIELD GUIDE
Rainwater killifish
FISH PROFILE
COMMON NAME
Rainwater Killifish
Scientific name
Lucania parva
FAMILY
Fundulidae
LENGTH
1 to 2.5 inches
DIET
Larval crustaceans, mosquito larvae, small worms, mollusks
FISH PROFILE
COMMON NAME
Rainwater Killifish
Scientific name
Lucania parva
FAMILY
Fundulidae
LENGTH
1 to 2.5 inches
DIET
Larval crustaceans, mosquito larvae, small worms, mollusks
DISTINGUISHING CHARACTERISTICS
The Rainwater Killifish is a small silver-yellow fish with a compressed body and a small upturned mouth. The fins of the male fish are a dusky orange to yellow, fringed with a thin black edge (except for pectoral fins) and usually have a black spot on the front of the dorsal fin. As adults, these fish can be between 1 to 3 inches. Smaller individuals can be confused with some mosquitofish species.
RANGE, HABITAT, and BEHAVIOR
Rainwater killifish can be found from Cape Cod, Massachusetts southward through the Atlantic, and in areas near the Gulf of Mexico. These fish can tolerate a wide range of salinities and are found in marshes, bays, lagoons, and springs. They tend to primarily inhabit brackish water in calm, vegetated area. Rainwater killifish usually swim several inches below the surface of the water and are commonly found in the St. John’s River system and in Florida’s springs. They feed on larval crustaceans, mosquito larvae, small worms, and mollusks.
FUN FACTS
The first reported description of the rainwater killifish was in 1855 by SF Baird and CF Girard, where it was given the scientific name Cyprinodon parvus. As more killifish were discovered, rainwater killifish were later added into the genus Lucania, and their species name was changed to Lucania parva in 1883 by DS Jordan and CH Gilbert. Lucania is a coined name that DS Jordan left undefined in the original description of the killifish genus, while parva means ‘small’.