Oarfish are large, greatly elongated, pelagic Lampriform fishes comprising the small family Regalecidae. Found in all temperate to tropical oceans yet rarely seen, the oarfish family contains four species in two genera. One of these, the king of herrings, is listed in the Guinness Book of World Records as the longest bony fish alive, at up to 17 metres (56 ft) in length. The common name oarfish is presumably in reference to either their highly compressed and elongated bodies, or to the former (but now discredited) belief that the fish “row” themselves through the water with their pelvic fins. The occasional beachings of oarfish after storms, and their habit of lingering at the surface when sick or dying, make oarfish a probable source of many sea serpent tales.
Rare encounters with divers and accidental catches have supplied what little is known of oarfish behavior and ecology. Apparently solitary animals, oarfish may frequent significant depths up to 1,000 metres (3,300 ft). In 2001 an oarfish was filmed alive and in situ: the 1.5 meter fish was spotted by a group of US Navy personnel during the inspection of a buoy in the Bahamas. The oarfish was observed to propel itself via an amiiform mode of swimming; that is, rhythmically undulating the dorsal fin whilst keeping the body itself straight. Perhaps indicating a feeding posture, oarfish have been observed swimming in a vertical orientation, with their long axis perpendicular to the ocean surface. In this posture the downstreaming light would silhouette the oarfishes’ prey, making them easier to spot.