Hadal Snailfish

British and Japanese researchers have released a vid of these fish that live almost 5 miles underwater. Footage after the deepest sighting below.

Is very very cool stuff; however in 1960 Jacques Piccard and David Walsh of the US Navy took a bathyscaph 35,600 feet down in the Marianas Trench.
Here's what Mr Piccard was quoted as saying, “…. And as we were settling this final fathom, I saw a wonderful thing. Lying on the bottom just beneath us was some type of flatfish, resembling a sole, about 1 foot long and 6 inches across. Even as I saw him, his two round eyes on top of his head spied us - a monster of steel - invading his silent realm. Eyes? Why should he have eyes? Merely to see phosphorescence? The floodlight that bathed him was the first real light ever to enter this hadal realm. Here, in an instant, was the answer that biologists had asked for the decades. Could life exist in the greatest depths of the ocean? It could! And not only that, here apparently, was a true, bony teleost fish, not a primitive ray or elasmobranch. Yes, a highly evolved vertebrate, in time’s arrow very close to man himself. Slowly, extremely slowly, this flatfish swam away. Moving along the bottom, partly in the ooze and partly in the water, he disappeared into his night. Slowly too - perhaps everything is slow at the bottom of the sea - Walsh and I shook hands.”