A new study has found that several species of Antarctic notothenioid fish succeed to survive in the cold waters of Antarctic by producing proteins similar to antifreeze.

The researchers said that this protein keep pieces of ice inside the fish from getting larger. But these proteins also contain an unintended consequence which may be harmful to the fish but they also keep the ice from melting.

The study showed that when the antifreeze proteins attach to a piece of ice, either inside of the fish or in a larger solution of water, the protein prevents the melting of ice even when the ice is heated beyond its normal melting point. Ice that remains solid beyond its normal melting point is called "superheated" ice. According to researchers, this is likely to be the first-ever discovered case of superheated ice found in nature.

The study is a collaboration between researchers from the University of Oregon and the University of Illinois and was led by Paul Cziko. The research team spent around two years studying Antarctic ice fish, such as the Antarctic toothfish. The study was focused to learn everything possible about how the fish survive in freezing waters. It is to be noted that this feature is not found in all fish living in Antarctica.

The researchers are currently busy in finding out how having tiny pieces of ice that remain intact inside the bodies of these fish affects the fish. Professor Chi-Hing "Christina" Cheng, one of the team's leaders, said that the ice may be harming the fish in some way.

Cziko remarked that it is likely that these ice pieces work similar to blood clots in humans.

"Since much of the ice accumulates in the fishes' spleens, we think there may be a mechanism to clear the ice from the circulation," Cziko said.