Coral-eating fish that camouflages its odour

Researchers have discovered a coral-eating fish that can disguise its odour to hide from predators.

The harlequin filefish that feeds on coral can also change its odour to match the coral where it shelters at night and remains undetected by predators.

"The harlequin filefish shelters among the branches of coral colonies at night, where not only does it look like a coral branch, it also smells like one, enabling it to remain undetected by nocturnal predators," said study co-author professor Philip Munday from the James Cook University in Queensland, Australia.

"For many animals vision is less important than their sense of smell," study lead author Rohan Brooker from the James Cook University said.

"By feeding on corals, the harlequin filefish ends up smelling enough like its food that predators have a hard time distinguishing it from the surrounding coral habitat," Brooker added.

Not only does the filefish confuse its predators, it matches the odour of the coral so closely that small crabs, which live on coral branches, cannot distinguish it from coral, the researchers found.

The ability to chemically 'blend in' occurs in some plant-eating invertebrates, but this is the first time this type of camouflage has been found in higher order animals, such as fishes.

The study was published in the journal Proceedings of the Royal Society B.