Widely distributed species (Naucrates ductor, family Carangidae) of carnivorous fish that inhabits warm and tropical open seas. It is slender and has a forked tail, a lengthwise keel on each side of the tail base, and a few small spines in front of the dorsal and anal fins. It may grow to 2 ft (60 cm) but is usually about 14 in. (35 cm) long. Five to seven distinctive vertical dark bands mark the bluish body. Pilot fishes follow sharks and ships, apparently to feed on parasites and leftover scraps. It was formerly thought that they were leading, or piloting, the larger fishes to food.