These are among Antarctica's 200 species of fish, and were first caught during an 1840 James Clark Ross expedition.
One hundred and twenty of these species are descendents of Notothenioids, which contain glycoproteins in their blood that work as "anti-freeze" proteins.
These proteins appeared in fish because of a genetic mutation that occurred 5-14 million years ago; since the waters were warmer back then, the proteins were not needed.
However, when continental plates shifted, what is now Antarctica broke off from South America, and produced such a strong current that warmer waters could not get through.
Therefore, the Antarctic seas became increasingly colder over time. The fish without the genetic mutation died out; today, each remaining Notothenioid carries the glycoproteins.
The proteins attach themselves to small ice crystals in the fish's body, enabling the fish to live in waters with temperatures as low as 28 degrees F.