A freshwater fish capable of surviving out of water for up to six days may also be able to survive in salty water, prompting scientists to warn that the aggressive climbing perch could make its way to mainland Australia from Papua New Guinea.

The fish, which can crawl across dry land and hibernate in dry creek beds for up to six months, has already made it to two small Torres Strait islands in Australian territory.

However ecologists hold serious concerns for the fate of native species if the climbing perch makes it to mainland Australia.

"They can breathe on land, they can walk across land with their gills and they can handle salt," said James Cook University aquatic ecologist Nathan Waltham.