Fish changes its smell to avoid being eaten


A new study has found a coral-eating fish that disguises its scent to hide from predators.

Research published in the Royal Society's flagship biological research journal, Proceedings B, discovered that the harlequin filefish, Oxymonacanthus longirostris, changed its smell to match the coral it fed upon.

"For many animals vision is less important than their sense of smell," says the study's lead author, Dr Rohan Brooker from the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

"Because predators often rely on odours to find their prey, even visually camouflaged animals may stick out like a sore thumb of they smell strongly of 'food'", says Dr Brooker.

The studies co-author, Professor Philip Munday says the ability to camouflage itself chemically is a great advantage for the fish.

"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."

Professor Munday says it's a remarkable example of how closely animals can be adapted to their habitats.

The ability to chemically camouflage occurs in some invertebrates but this is the first time this biological process has been discovered in higher order animals like fish.

"This is very exciting because it opens the possibility of a wide range of different animals also using similar mechanisms, right under our noses," Dr Brooker says.