Oarfish Regalecus glesne
At up to 36 ft (11 m) in length, the oarfish is the longest bony fish known to science and is thought to be responsible for many sea serpent legends. Its bizarre appearance is enhanced by a crest of long red rays on its short, bluish head, which are followed by a bright red dorsal fin that runs the length of its silvery body.
Its name comes from the pelvic fins, both of which extend as a single, long ray ending in an expanded tip, which looks like the blade of an oar. In the open ocean, the oarfish drifts in the currents, feeding on other fish and squid, its great length protecting it from most predators. Although it lives in tropical and temperate waters worldwide, the oarfish is rarely caught or seen alive, so little is known about its behavior. It was first photographed underwater in 1997 in the Bahamas.
Photo of the oarfish replica in the Smithsonian Museum of Natural History, taken by Tim Evanson and shared under the Creative Commons Attribution-Share Alike 2.0 Generic license