American Flagfish

From Microcosm Aquarium Explorer

Jump to: navigation , search
Jordanella floridae - Goode & Bean, 1879
American Flagfish

A native North American killifish: male, fore, female at rear. Matt Wittenrich


The American Flagfish is a native killifish from Florida and a charming, unusual aquarium species. They prefer to live in schools of their own kind in a quiet, dimly lit tank. They are somewhat shy, but can be quite personable with their keepers. A happy Flagfish displays beautiful color and iridescence, and the pattern of the male truly does resemble Old Glory. Females are smaller, with a black spot at the rear of the dorsal fin.

This species has been listed in the Guiness Book of Records as having the fewest eggs per spawn--just 20 produced over several days.

See Secrets of the American Flagfish and Tracking the Elusive Flagfish.

Family: Cyprinodontidae

Other common name(s):

  • Flagfish
  • Florida Flagfish
  • American-Flag Fish
  • Flag Fish

Native range:

Habitat: In the wild, it is found in brackish and freshwater marshes, ponds and canals and irrigation ditches in the Florida peninsula. It displays best in an aquarium with darker substrate (when placed in a tank with light-colored gravel, it assumes a pale appearance).

Maximum length: 6 cm (2 in)

Minimum aquarium size: 37 L (10 gal)

Lighting: Dim to medium light, but a sunny tank is also appreciated.

Water: Freshwater 20 °C (68 °F) - 30 °C (86 °F)

General swimming level: Midwater to bottom.


Omnivore with an appetite for algae and other green foods, in addition to worms, small crustaceans, and dried insects.

Aquarium Compatibility

Best kept in groups of one male and three females. The male is territorial, but will not molest larger or armored fishes (like Plecos.) The males are very hard on fishes with long fins, particularly Bettas, and will harass a lone Flagfish female.

Special Care

While this fish will tolerate a wide variety of aquarium conditions, it should be acclimated well before introduction to a new aquarium.


These fish enjoy an intense courtship dance after which the female lays about 5 eggs that are fertilized by the male. He either makes a nest at the bottom, attaching each egg to a strand of Java Moss or thread of algae or in floating plants at the surface. He guards and fans the eggs (sometimes when he doesn't even have any eggs to show the female how industrious he is.) The eggs hatch into the tiniest of fry after about 5 days. In about two weeks, move the fry to their own tank, preferably one with a heavy growth of algae and green water. To see Florida Flagfish spawning, go to:

Reference: A PocketExpert Guide to Freshwater Fishes
Image credit: MW
Text credit: MES