The fish live in temperatures of -0.5°C to -1.8°C and die in temperatures over 6°C, the lowest known temperature to kill an animal.

According to the so-called specialisation paradigm, the rock cod belongs to a group of animals known as stenotherms.

The theory says stenotherms have traded off their ability to function in a specialised environment for an inability to handle changes in that environment.

But Seebacher says his research has dispelled that paradigm.

"We ... hypothesised that when exposed to longer-term changes, the fish would compensate for those changes," he says. "We have shown that this occurs."