Perhaps you've seen some of those old maps of the world from the 1600s. You know the ones I'm talking about, with the slightly malformed continents and the little drawings of leviathans and sea serpents in the oceans. I bet when you first saw them you pointed at the fish and said something like "Ha ha! They thought mythical creatures were real!". And you probably felt very smug about your superior, modern understanding of the natural world.
Later, you might have heard that whales and/or sharks were the inspiration for such sea monsters. It's a theory that seems reasonable enough; they might not look like sea serpents, but hey, people back then were dumb enough to think manatees were mermaids. I mean, come on. There's no such thing as a real sea serpent.
But there is. And its name is Regalecus glesne, more colloquially known as the Oarfish. Physically terrifying, the Oarfish can be as long as 39 feet (12 meters), though there are unconfirmed reports of specimens reaching lengths as long as 60 feet (15 meters). It sports a massive jaw, comparable in size to many sharks, and a vibrant pink dorsal fin that crests above its head like a crown, earning it the title "King Of The Herrings". There are even reports of the creature giving off electric shocks when touched, though the veracity of such a statement is questionable.
But despite its imposing appearance, the Oarfish is almost completely harmless- it feeds on zooplankton for the entirety of its life cycle. At least, as far as we know it does. Observation of Regalecus glesne in the wild has been limited by the incredible depths at which the creature apparently lives. Indeed, they would be completely unknown were it not for the odd specimen that works its way to the surface when ill or washes up on shore after a storm.
As a result, most of what we think we know about this organism is based on anatomical guesswork. The jaw, despite its size, is mostly toothless, thus the assumption of feeding on zooplankton (that and the contents of the stomachs in recovered specimens). It is not out of the question however, that the Oarfish might also be a predator of small fish and shrimp.
The first video of a living Oarfish, which was captured in 2001, supports this theory to an extent. The Oarfish was observed as swimming on the vertical rather than horizontal plane, possibly to widen its range of view in the hopes of glimpsing prey silhouetted by the sun (or maybe just to see predators before they saw it).
The largest bony fish in the world, Regalecus glesne is an animal that inspires a certain degree of awe and inspiration for the ability of the ocean to produce magnificent and remarkable life forms. With creatures like this only recently emerging into the eyes of science, the door is opened for other apparently mythical creatures to reveal themselves. Nessie, anyone?
Three Oarfish Images for illustrative purposes. The second image compares two different Oarfish caught in Mexico (top) and Thailand (bottom). The full range of the fish is unknown. The first (second image in the gallery) and third images highlight the black dots and squiggles that cover the fish's body and dissipate shortly after death for reasons as of yet unknown.