Banded Killifish (Fundulus diaphanus) - Native

7 cm banded killifish.

A 3-inch male banded killifish.

Identification. Streamlined shape. Similar to mummichog, but with a more slender caudal peduncle and body and the dorsal fin is set farther forward (distance from first dorsal ray to beginning of tail fin about equal to distance from first dorsal ray to middle of eye). Usually has 12-20 dark vertical bands on sides. Lateral-line scales greater than 40. Base of first dorsal ray directly over or slightly ahead of first anal ray. Typically dark gray on back fading to bluish gray on sides and white to yellow on belly. Spawning males develop yellowish lower fins and iridescent bluish or purplish casts on their sides.

Three banded killifishes.

Three banded killifish, a male (top) and presumably two females (center and bottom).

Size. Commonly 2 to 3 inches. State survey max. size 4.3 inches. Max. reported size 5 inches.

Distribution. North America, primarily within the United States from Wisconsin to Newfoundland and south to South Carolina. In Connecticut, the banded killifish has a patchy distribution within all major watersheds. They are typically common where found.

Banded Killifish distribution map.

All maps created in 2009. See CT DEEP Fish Community Data for updated distributions.

Habits. Prefer shallow, still areas of lakes and ponds and slow-flow areas of larger rivers and streams. Usually found over sandy bottoms, often near vegetation. Moderate-size schools are often seen in very shallow water (less than 6 inches deep) of lakes. Can be captured with a small-mesh dip net or seine.

Typical banded killifish.

A robust, 4-inch banded killifish from the lower Connecticut River.

Comments. Our only freshwater killifish species, although estuarine populations occur in the lower reaches of most Connecticut coastal rivers and streams.


Text and images adapted from Jacobs, R. P., O'Donnell, E. B., and Connecticut DEEP. (2009). A Pictorial Guide to Freshwater Fishes of Connecticut. Hartford, CT. Available for purchase at the DEEP Store.