Oceans are home to some of the strangest creatures in the entire planet. Remember the adorable sea slug with beady eyes and floppy feelers that looks like a cute cartoon sheep? More fascinating perhaps is Marcopinna microstoma, a tiny deep-sea fish that sports a completely see-through head. Peeping through the fluid-filled, transparent dome is a pair of droopy eye-like dots that actually serve as its nostrils. Its real organs of vision, however, are the two brownish tubes leading to the bright green half spheres.

Originally discovered in 1939, M. microstoma was photographed for the first time only in 2004, by researchers from the Monterey Bay Aquarium Research Institute (or MBARI). Found at depths of around 2,000 ft up to 2,600 ft in the ocean, the fish is a type of barreleye, called so because of its barrel-shaped, tubular eyes. It doesn’t generally swim, spending most of its time lying motionless in the water, with the help of its rather large and flat fins.

According to the experts at MBARI, the 6-inch-long fish uses its eyes, which are usually pointed upwards, to discern prey in the murky depths. When it comes across a smaller fish or jellyfish, the creature moves into a vertical position, rotating its eyes forward so as not to lose sight of the food. Scientists believe that the bright green hemispheres actual help block sun’s rays, thus allowing the barreleye to spot its prey’s bioluminescence more efficiently.

But why are its eyes present inside the head, you wonder? Well, the scientists at MBARI are of the opinion that it helps the fish take food off the tentacles of siphonophores, a jellyfish-like marine animal, without getting their eyes stung.

Via: The Dodo