Marine Animal Encyclopedia
Oarfish Regalecus glesne
With claims of individuals reaching 50 feet long (15 m) and confirmed individuals reaching 35 feet (10.5 m), the Oarfish is the longest bony fish in the world and has a spot in the Guinness Book of World Records to prove it.
Though reaching these extreme lengths, Oarfish are extremely thin, from side to side, and the maximum recorded weight of an Oarfish is approximately 600 pounds (272 kg). While that may seem quite heavy, it is not very much for a fish that may reach lengths longer than a school bus. As a result of this general shape and the bright, silvery coloration and long, red fins, some people around the world know the Oarfish as the Ribbonfish. The first few elements of the dorsal fin are long and wispy, resembling a crown, and give rise to yet another common name for this species, the King of Herrings. Oarfish have very large eyes that they use to see in the extremely low light conditions of the deep parts of the open ocean [link to pelagic ocean page], their preferred habitat. They rarely come to the ocean surface, perhaps only when dying or disoriented, and occasionally wash up on beaches around their home range (all tropical to warm temperate seas). Most individuals that are discovered near the surface or near beaches do not survive. Unlike most fishes, the Oarfish’s body has no scales.
Oarfish are likely the source of sea serpent myths that are part of most maritime cultures around the world. Some observers report that Oarfish discovered at the sea surface often swim with their head and ornate “crown” out of the water as if they are searching for something. This curious behavior, the long snake-like body, and the relative rarity with which they are observed at the sea surface (most notably after large storms) all feed the belief that mythical sea serpents attack mariners or even entire ships in the open ocean. However, Oarfish are quite harmless. They have very small mouths and no teeth, and they feed by filtering small prey from the water, swimming with their mouths open and capturing their food with modified bones that support their gills.
Though the Oarfish is assumed to be naturally rare, the difficulty of studying it in its preferred natural habitat (the deep, mostly dark water column) has prevented scientists from assessing its conservation status or the likelihood that it may become threatened with extinction.