A species of damselfish, Stegastes nigricans, selectively weed the algal gardens on which they feed in order to encourage the growth of their preferred algal species of Polysiphonia and suppress the growth of less palatable algae.

Damselfish are killing head corals and adding stress to Caribbean coral reefs, which are already in desperately poor condition from global climate change, coral diseases, hurricanes, pollution, and overfishing.

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

Two species of damselfish may look identical—not to mention drab—to the human eye -- But that's because, in comparison to the fish, all of us are essentially colorblind.