The Lookdown (Selene vomer) has an extremely deep and laterally compressed body with very small, embedded scales. The overall color is iridescent silvery to golden, with a metallic bluish tinge on the dorsal (top) surface. The dorsal ("back") and ventral ("belly") profiles are straight anteriorly (i.e., toward the front) and nearly parallel. The front profile of the head is very steep, with a mouth near the bottom. On each side of the body, the lateral line is arched upward anteriorly.
In adults, the pelvic fins (the anteriormost fins toward the underside of the fish) are very short. The first dorsal fin (on the fish's back) has eight spines, which are persistent. The second dorsal fin and the anal fin are long and falcate (sickle-shaped). The anal fin consists of two free spines followed by one spine and 17-20 rays, with the anterior rays elongated and forming an acute lobe. The two free anal spines are resorbed as the fish grows. Free anal fins are absent in individuals greater than 11 cm FL. ("Forklength" [FL] is the length from the tip of the snout to the end of the middle caudal [tail] fin rays; this length measure is used for fish species in which it is difficult to determine where the vertebral column ends and the tail fin begins, as is necessary for the more common "standard length" [SL].) Unlike adults, young fish have long pelvic fins and long streamerlike flaments extending from the first dorsal spines. In adults, the second dorsal and anal fins are greatly extended. This transition is complete by the time the fish reaches 10 to 12.5 cm. Juveniles also have a dusky, slightly oblique crossband and band over the eye. See McEachran and Fechhelm (2005) for a more detailed morphological description.
Lookdowns occur in shallow coastal waters over sand or mud in the western Atlantic from Maine to Uruguay, including Bermuda, the northern and southern Gulf of Mexico and the Greater Antilles. They travel in schools and feed near the bottom on crustaceans and other fishes. Maximum known size is 40 cm FL.
(Boschung et al. 1983; Robins and Ray 1996; McEachran and Fechhelm 2005)