The Barreleye fish with a transparent head!

By in Animals

Even the phrase “seeing is believing” is not enough when looking at this astonishing fish! Meet Macropinna microstoma, commonly known as the “barreleye”. Barreleye fish have a transparent head with large internal eyes that are able to look upward. Living at depths of 600 to 800 meters below the surface, these ultra-sensitive eyes help these fish search for the faint silhouettes of prey overhead.

Barreleye fish head

Although facing downward, the barreleys is looking straight up. Photo by MBARI.

These fascinating fish were first described in 1939. However, only recently researchers found that the fish’s eyes aren’t fixed in place, but can rotate behind the transparent shield on the barreleye’s head. This allows the Barreleye to peer up at potential prey or look forward when the fish is feeding. The two spots above the fish’s mouth are olfactory organs which are analogous to human nostrils.

Barreleye fish face

This face-on view of a barreleye shows its transparent shield lit up by the lights of MBARI’s remotely operated vehicle. Photo by MBARI.

In addition to their amazing eyes and heads, barreleyes have a variety of other interesting adaptations to deep-sea life. Their large, flat fins allow them to remain nearly motionless in the water and to maneuver very precisely.

Barreleye fish

The barreleye has extremely light-sensitive eyes that can rotate within its transparent, fluid-filled head. Photo by MBARI.

Barreleyes share their deep-sea environment with many types of jellyfish, of which the most common ones grow over 10 meters and trail thousands of stinging tentacles. Scientists speculate that the fish’s special rotating eyes to help them carefully maneuver among the tentacles, while the translucent head would protect the fish’s eyes from the jellies stinging cells.

  • http://- jasper

    haha dit is echt te vet!

  • Linzy

    this article is great. i love it when i see something that seems too incredible to be real! thanks :)

  • Pieter

    Ha Jolle,
    Cool stuff dude. Very nice website, i can’t believe how much info is here, all including references and stuff. I’m not much of a websurfer but I might start on that after seeing this.
    P.s. don’t forget we have a study lined up (piano), which month would work best for you?

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  • Bob


  • Kara

    WOW! I’ve never seen any thing like this before. It just looks so fake Haha..

  • yog
    to know more about it…

  • Antonio R. Wyckoff

    This just attests to the Lord God’s Wonderful wisdom and sovereignty! There has never been a work of art that didn’t have an artist.!!! Love it!!

  • Jolle Jolles

    Antonio, thanks for expression you admiration about this wonderful species. As you will understand I don’t agree with what you say though :) Nature is perhaps for many full of things hard to believe to exist without being created by higher being, but they as they appear now are the result of thousands and thousands of years of natural selection. There is no end goal in evolution or natural selection, there is simply the survival of the fittest and those individuals only will pass on their genes to the next generation. Nevertheless, whatever you believe, it is great to be amazed by our wonderful natural world and therefore try and preserve it as much as possible!

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  • mika

    how do barreleye reproduce