Killifishes (Fundulidae)

Killifish silhouette.

The killifishes are a moderately large family with both marine and freshwater members distributed throughout Central and Eastern North America from southern Canada to the Yucatan, including Cuba and Bermuda. They are generally small, schooling fishes (usually less than 6 inches). Superficially they look like minnows, but have toothed jaws, scales on top of their heads behind the eyes, and small distinctively shaped, upturned mouths. They have a single soft dorsal fin and a square or rounded tail. The pelvic fins are abdominal.

There are five native species of killifish in Connecticut. Four are found strictly in estuarine/marine environments, one in predominantly fresh water. Males and females typically have different markings or colors.

Click on species' names below to learn more.

Banded Killifish (Fundulus diaphanus) - Native

7 cm banded killifish.


Mummichog (Fundulus heteroclitus) - Native

8 cm mummichog.


Striped Killifish (Fundulus majalis) - Native

11 cm male striped killifish.


Spotfin Killifish (Fundulus luciae) - Native

Spotfin killifish.


Rainwater Killifish (Luciana parva) - Native

Rainwater killifish.


Killifish are relatively easy to keep in home aquariums, but don’t do as well in the presence of large, aggressive species. They will take dried flake food, but do best with at least some live, freeze-dried or frozen food offerings. All species except the banded killifish require at least some salinity in the water. Killifish tend to school by size in the upper levels of the tank and may nip the fins of tank mates.


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.