Barreleye Fish Have Eyes INSIDE Their Transparent Heads

Barreleye fish close up

Mother Nature has brought a whole new meaning to being able to “see right through” someone–or something, in this case. More than 2,000 feet deep in the Pacific Ocean, the “barreleye fish” (or Macropinna Microstoma, if you want to get technical) hides no secrets from outside viewers in it’s pitch-black environment. With a unique, completely transparent head, few other sea creatures had scientists so intrigued. After first being described in 1939, marine biologists have been doing research on these fish, and especially curious about it’s tubular eyes, which are highly skilled at collecting light.

Take a closer look, though. The eyes aren’t actually the two small circles above the mouth–they’re actually the bright green tubes INSIDE the clear head. The circles above the mouth are actually the fish’s olfactory organs called nares (what we would compare to human nostrils).

The barreleye fish’s note-worthy traits don’t end there, though. Its large, flat fins allow the fish to stay almost completely motionless in the dark water, waiting for prey. Its eyes can search for food both directly above the fish’s head AND in front of it by rotating within the clear, fluid-filled head, or “shield”. Oh yeah, and these fish also eat unsuspecting jellyfish. Crazy, right? Take a look at this rare footage of the barreleye fish in the wild, and get even more unbelievable facts about them in a report from the Monterey Bay Aquarium Research Institute.

What do you think?