The Spookfish or the Barrel Eye is a very strange creature indeed. There are several different species, but they are quite interesting, and easily picked out by their large ‘barrel’ eyes and transparent skulls.
Those two sleepy looking little eyes right above its mouth of the fish in this video are actually “nostrils”. The eyes are the big round globes inside the skull, with the green caps on top of them.
This fish actually looks through the top of its own skull to see.
Other Spookfish eyes are separated into two parts, one seeing upwards, the other down, effectively giving it four eyes. How this works is not so clear in the video above, but in different species, the head shape makes how this is possible more apparent. The eyes protrude more out of the sides of the head, allowing vision below the fish.
Even stranger, it is it is the ONLY known creature to use mirrors to focus its eyes. This allows for a greater use of less light, pulling in light and focusing it upon the retinas.