The longest fish in the world :Oarfish

An oarfish can easily be mistaken for a sea serpent, but they are really the longest bony fish in the sea, growing to fifty feet or more in length. The longest oarfish alive according to the Guinness Book of World Records is 36 feet in length.
Oarfish are rare but found worldwide in tropical and temperate waters at depths from the surface to 3,000 feet. Not much is known about their habits and life cycles, but they probably only come to the surface when injured or dying. They feed on very small fish, shrimp, and other invertebrates that they filter through their toothless mouths. Oarfish have shiny, silvery bodies, bright red crests on their heads, and are also known as ribbon fish.