Wikipedia
Fundulidae
Fundulidae is the family of topminnows and North American killifishes. The 46 species are native to North America as far south as Yucatan, and to the islands of Bermuda and Cuba, occurring in both freshwater and marine environments.
Members of the family are all small; while the giant killifish (Fundulus grandissimus) and northern studfish (F. catenatus) reach in length, most species are under 10 cm.
The distinguishing characteristic of the family is the maxillary bone, which is twisted instead of being straight.