pilotfish

[ pahy-luh t-fish ]
/ ˈpaɪ lətˌfɪʃ /

noun, plural (especially collectively) pi·lot·fish, (especially referring to two or more kinds or species) pi·lot·fish·es.

a small, marine fish, Naucrates ductor, often swimming with sharks.
any of various other fishes having similar habits.

Origin of pilotfish

First recorded in 1625–35; pilot + fish

British Dictionary definitions for pilot fish

pilot fish

noun

a small carangid fish, Naucrates ductor, of tropical and subtropical seas, marked with dark vertical bands: often accompanies sharks and other large fishes
any of various similar or related fishes