Swordfish (Xiphias gladius)
The swordfish, as the only member of the family Xiphiidae, can be distinguished from other billfishes (Family Istiophoridae) by the shape of its prolonged "bill", which appears as a flattened oval in cross section. The bill is long relative to other billfishes and adults lack teeth in the jaws. While the young have scales, these are lost by the time the fish attain a body length of about 3 feet (1 m). Adults lack scales and teeth. The body is generally cylindrical. Two dorsal fins are present, although the second is quite small, separated from the first, and set far back on the body. The first dorsal fin is high and rigid. Likewise, there are two anal fins, although again the second is considerably smaller than the first. Pelvic fins are absent. The caudal fin is lunate, while the caudal peduncle has a pronounced keel on either side. The lateral line is also present in specimens up to 3 feet (1 m) in body length, but it too is lacking in adulthood. Prior to adulthood, swordfish morphology changes greatly, as described below. The colour is blackish-brown above, fading to a lighter shade below. The fins are brown or dark brown.