'rudderfish' originates from the combination of 'rudder' and 'fish', where 'rudder' refers to the steering part of a ship, and 'fish' refers to the aquatic animal.

'Rudderfish' has been used in English since the 19th century to describe fish with a prominent dorsal fin resembling a rudder.

Initially, it referred to any fish with a rudder-like fin, but now it specifically refers to certain species like the pilot fish.