Percoids have elongated, fusiform bodies with forked or slightly forked caudal fins. Bluefishes have two dorsal fins, a long anal fin, and a mouth well armed with sharp, compressed teeth arrayed in a single series. They grow to about 51 in (130 cm) in length. Adult male dolphinfishes have pronounced bony crests on the heads; these fishes also have long, continuous dorsal and anal fins and brilliant yellow, green, and blue coloration. They grow to about 83 in (210 cm) in length. The roosterfish has an elongated, fusiform body with a raised head profile dor-sally and a dorsal fin containing seven remarkably long spines. The remoras are streamlined, elongated, or club-shaped, with a flattened head that has a sucking disc modified from a dorsal spine. The disc has between 10 and 28 movable lamina that allow it to grasp the body surface of a host. The dorsal fin is positioned just ahead of the caudal peduncle and has 18-40 soft rays. The anal fin also has 18-40 soft rays. The scales are cycloid and small, and the swim bladder is absent. Remoras have a highly modified dorsal surface on the head that acts as a suction disc. This disc allows remoras to attach themselves to the body surfaces of various hosts. Body coloration ranges from black to combinations of blue, black and white. Body sizes range from 20 to over 44 in (50 to over 110 cm). Remoras are remarkably adapted for a commensal relationship with numerous host organisms and clean their hosts in exchange for "hitching rides" and feeding on leftover food items. The blue-fish, the dolphinfishes, and the roosterfish have evolved to become efficient predators in open waters or inshore habitats.
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