You might have heard about the giant oarfish (Regalecus glesne) recently in the news, since two specimens at the astonishing lengths of 18 and 14 feet were washed up in Southern California only 5 days apart from each other in October 2013. An image of one:
Thought to be the origin of many “sea serpent” stories, oarfish are rarely seen (normally found at a depth of up to 1,000 meters) but can be found in all temperate to tropical oceans. They are found beached after storms or on the surface of the water when sick or dying. Oarfish are lampriform fish (order Lampriformes) that can grow to be 11 meters (36 feet) long, making them the largest bony fish alive. Their dorsal fin extends along the entire length of their body, and they swim by undulating this fin while keeping their body straight. They also have been observed swimming in a vertical position, which might assist in feeding.