Secret markings help reef fish

In a remarkable new finding, scientists have reported that certain coral reef fish use ultraviolet (UV) vision to tell the difference between their own and other similar species.

Indeed, the otherwise rather plain-looking Ambon damselfish may even be able to recognise individuals by their faces, in much the same way as humans do, the researchers say in a paper in the latest issue of the journal Current Biology.

The UV vision may act as a secret channel of communication because it is invisible to the fishes’ predators, the researchers speculate.