Bowfin are easily identified by their elongate dorsal fin, which undulates when swimming. Bowfin also possess nostril tubercles and a gular plate. Juveniles have a yellow-ringed ocellus located in the upper portion of the caudal peduncle which is retained in adult males, but often lost or reduced to a black spot in adult females.
Amia calva is a facultative air-breather and possesses a modified gas bladder which serves as a lung. During levels of high activity and/or low dissolved oxygen, bowfin use their lung to breathe air.