The Pilot fish (Naucrates ductor) is a carnivorous fish that is a horse mackerel and belongs to the Carangidae family of fishes. It is widely distributed and lives in warm or tropical open seas.
The Pilot fish is known for following large vessels and sharks, where it feeds on parasites and leftovers. Its relationship with sharks has been described as nearly symbiotic: it is extremely rare that a shark will feed on a pilot fish, and smaller pilot fish are frequently observed swimming into sharks’ mouths to clean away fragments of food from between their teeth. Anecdotal evidence suggests that ancient Greek sailors believed that pilot fish, which would appear around their ships when they were close to land, were leading (or piloting) them back to port, and so they were named. It is sometimes suggested that pilot fish were thought to be piloting larger fish to food as well.
The pilot fish has distinctive black and white markings; this observation has led to similar markings being used in decals supplied as shark protection for surfboards.