One of the ocean's strangest looking fish of all is the deep-sea angler fish. The deep-sea angler fish is known scientifically as the Melanocetus johnsoni and is one of the deep ocean's most well known residents. The angry-looking deep sea angler-fish has a right to be cranky. It is quite possibly the ugliest animal on the planet, and it lives in what is easily Earth's most inhospitable habitat: the lonely, light-less bottom of the sea.
As Wikipedia says,
Anglerfishes are members of the teleost order Lophiiformes. They are bony fishes named for their characteristic mode of predation, wherein a fleshy growth from the fish's head (the esca or illicium) acts as a lure; this is considered analogous to angling.Their most distinctive feature, worn only by females, is a piece of dorsal spine that protrudes above their mouths like a fishing pole—hence their name. Tipped with a lure of luminous flesh this built-in rod baits prey close enough to be snatched. Their mouths are so big and their bodies so pliable, they can actually swallow prey up to twice their own size.
Any fish which passes before the angler fish’s eyes can be its prey. Anglerfish’s diet is filled with various genres of fishes. They eat almost all kind of sea worms, batfish, clams, copepods, and marine snails. The predator fish eats even the fishes, which are almost double the size of it.
Finally, the Angler Fish from the movie "Finding Nemo" :-)