Few fish can survive the immense pressure of living in the deep sea. The Mariana Trench can reach around 36,200 feet deep with pressures of over 1,000 atmosphere. Scientists have placed landers at various depths ranging from 16,400-34,750 feet along the walls of the trench and have discovered what appears to be the “World’s Deepest Fish”. The fish was found at 26,872 feet which is estimated to be near the lower limit for bony fishes (of 27,600 feet). This newly discovered fish has what look like wings and tentacles. The video below was captured by the Hadal Ecosystem Studies expedition (HADES) sponsored by the National Science Foundation. Without a live specimen, however, it remains nameless.

Fish living in the deep ocean have large amounts of a chemical called TMAO (trimethylamine N-oxide), which not only helps to regulate the cellular osmotic balance but also ensure proteins stay folded properly. Turns out the deeper a fish lives, the more TMAO it has.

Not surprisingly, ocean fish are not as salty as their environment. Keeping in mind the mantra that “water follows salt”, this protein (among other mechanisms) helps prevent the fish from losing water to the environment and hence prevents dehydration. TMAO does this by helping to increase the osmolarity of fish.


Yancey PH, Gerringer ME, Drazen JC, Rowden AA, Jamieson A. (2014). Marine fish may be biochemically constrained from inhabiting the deepest ocean depths, Proceedings of the National Academy of Sciences, 111 (12) 4461-4465. DOI:http://dx.doi.org/10.1073/pnas.1322003111

Scientific American


  1. #1 G
    January 12, 2015

    I couldn’t help but think “somewhere under the surface of one of the moons of Jupiter or Saturn…”

    Astrobiologists ought to be highly interested in the findings on deep-water fish and extremophiles: these would set parameters (limits) for the existence of various types of life on Earth, and could be applied to other planets and their satellites to make inferences as to whether known types of life might be possible there.

  2. #2 Gregory Petrossian
    January 16, 2015

    I am so interested in deep-sea fish. I always wonder what could be so deep down in the ocean and how they are able to survive in such dark, cold temperatures. I love seeing the evolutionary differences between regular fish and deep sea fish. I did research on a type of deep-sea fish called the humpback anglerfish (http://en.wikipedia.org/wiki/Humpback_anglerfish) and what they do in order to survive. I actually learned that the male humpback anglerfish is about 3 cm smaller than the female humpback anglerfish. I wonder why!

  3. #3 Allen
    January 16, 2015

    Some great video. Thanks for sharing. I wish we could have gotten a clear image of its face. However, all things considered, this is a really great image of this new fish.

  4. #4 Taryn Rudling U15015719
    South Africa
    March 10, 2015

    Wow that was an amazing video, I cannot believe how beautiful and almost angel like the fish looked. This just makes you wonder how many of interesting species are down there to be discovered. Thank you Gregory for sharing that extra information because it is very fascinating to see how these different animals have adapted or evolved over time to suite their environment such as the use of TMAO. I am just curious to know if they have discovered any information about this fish with regards to what it would feed on this far down in the sea?

  5. #5 leku
    south africa
    April 6, 2015

    Wow, beautiful other worldly creature. I was wondering if the fish fed on plankton like creatures?

  6. #6 Alfonso
    Cape Town
    April 8, 2015

    Wow this is really interesting. Look forward to hearing what more information they can gather from this.