Rainwater Killifish

Lucania parva is a remarkably euryhaline killifish native to coastal marshes, tidal creeks, estuaries, and freshwater streams along the Atlantic and Gulf coasts from New England to Mexico. Its ability to tolerate salinity from fresh water to full sea water makes it an extraordinarily versatile aquarium fish. Males display attractive iridescent blue-silver scale patterning and yellow-orange fin pigmentation in breeding condition.

In the aquarium, Rainwater Killifish can be maintained in fresh, brackish, or marine-aquarium conditions, making them uniquely flexible. In freshwater setups they thrive in a range of conditions from soft to hard; in brackish setups a specific gravity of 1.005–1.015 suits them well. They are surface-oriented and should always have floating plant cover and a tightly fitted lid.

They are peaceful, hardy, and adaptable — ideal beginner killifish that introduce the keeper to native surface fish without demanding specialised conditions. They breed readily, depositing adhesive eggs on fine plants, and fry are easily raised on micro-foods.

Water: 10–28 °C, pH 7.0–8.5, fresh to brackish (up to SG 1.020); highly adaptable. Tank: 40 L minimum; floating plants essential; tightly fitted lid; tolerates salt additions. Feeding: Live/frozen Daphnia, Artemia, small insects; floating flake and micro-pellets accepted. Breeding: Eggs attached to plant roots and fine plants; easy to breed; fry accept Artemia nauplii. Compatibility: Peaceful; compatible with other small euryhaline or freshwater native species.