Tiny glowing fish is full of antifreeze to help it survive Greenland's icy waters

The tiny snailfish is full of antifreeze proteins and also glows in green and red.

(CNN)A tiny fish that lives in the icy waters off the coast of Greenland may be unassumingly small, but scientists have found it's exceptional in more ways than one.

The variegated snailfish is full of naturally occurring antifreeze proteins at previously unseen levels that help it survive in subzero waters, according to new research. The snailfish, known as Liparis gibbus, is also distinctive thanks to biofluorescence, which makes it glow in green and red.
Study authors David Gruber and John Sparks, both research scientists at the American Museum of Natural History in New York City, were on the Constantine S. Niarchos Scientific Expedition in 2019 when they spied a glowing snailfish off the coast of East Greenland.
    Biofluorescence occurs when animals have the ability to convert blue light into green, red or yellow light. This trait is incredibly rare in Arctic fish, who live in extended periods of darkness. So far, the variegated snailfish is the only known polar fish to have this glow.
      Researchers dove off the coast of East Greenland to study tiny snailfish.
      Gruber and Sparks collected a juvenile snailfish only about 3/4 inch (1.9 centimeters) long -- about the size of a fingernail -- compared with the average 4.5-inch (11.4-centimeter) length of an adult.
        The scientists wanted to learn more about the snailfish's biofluorescent properties when they stumbled on something else in the fish's genetics: the highest expression levels of antifreeze proteins ever observed.
        "Similar to how antifreeze in your car keeps the water in your radiator from freezing in cold temperatures, some animals have evolved amazing machinery that prevent them from freezing, such as antifreeze proteins, which prevent ice crystals from forming," said Gruber, a research associate at the American Museum of Natural History and distinguished professor of biology at the City University of New York's Baruch College, in a statement.
          "We already knew that this tiny snailfish, which lives in extremely cold waters, produced antifreeze proteins, but we didn't realize just how chock-full of those proteins it is -- and the amount of effort it was putting into making these proteins."
          As Arctic waters continue to warm due to the climate crisis, however, the future of the variegated snailfish, with its remarkable adaptation to the cold, is uncertain, said study coauthor John Burns, senior research scientist at the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine.
          The journal Evolutionary Bioinformatics published the findings on Tuesday.
          David Gruber (left) and John Sparks (right) investigate an iceberg in eastern Greenland.
          Polar oceans are extreme environments for marine life and only creatures who have adapted to live within the freezing temperatures can survive there.
          Some species of insects and rept