The defence secrets of a tiny, leaping, amphibious fish, unveiled by NSW scientists, may give an insight into how life survived the transition from aquatic to terrestrial habitats.
The Pacific leaping Blenny grows to only eight centimetres and spends its time leaping from rock to rock, defending territory and feeding on the tropical island of Guam.
Dr Terry Ord and Courtney Morgans from the University of NSW first compared the colours of five Blenny populations with the rocks they lived on.
After discovering the colours were almost identical they modelled Blenny lookalikes out of plasticine and placed them in the habitat.
Dr Ord said the models were collected after several days and the incidence of attacks from birds, lizards and crabs recorded.
"We found the models on the sand were attacked far more frequently than those on the rocks," he said in a statement.
"This means the fish are uniquely camouflaged to their rocky environments and this helps them avoid being eaten by land predators."
They also found closely related fish had similar colouration, meaning the Blenny's ancestors were probably rock coloured when they first moved out of the water.
"These species provide an evolutionary snapshot of each stage of the land invasion by fish," said Dr Ord.