Bayou killifish also resemble the diamond killifish, but have no pointed snout as the diamond killifish does.

Adinia xenica, the Diamond killifish, is a species of North American killifish found along the Gulf Coast of the United States.

Formerly placed in Fundulus were the closely related diamond killifish (Adinia xenica) and the somewhat more distantly related Cuban killifish (Cubanichthys cubensis, a pupfish).

There are a few Killies that prefer brackish water, such as the Diamond Killie Adinia xenica and Jordanella floridae the American Flagfish, found in the Florida Everglades.