type of warm-water fish, 1630s, from pilot (n.) + fish (n.). So called because they were thought to lead sharks to prey. It is uncertain whether this is the same fish known to the Ancients as pompilus (Greek pompilos, "pilot").
also red-fish, 15c., used of various species in different places and times, especially originally the male salmon in spawning season; from red (adj.1) + fish (n.). So called for their color or markings.