Many of us are familiar with the scenes at cleaning stations, where cleaner fish and cleaner shrimp feed on the parasites and dead tissues of their “clients.”

Under normal circumstances, sharknose gobies (Elacatinus evelynae) would set up a cleaning station at a coral reef, and use it as a base to attend to their “clients”—usually the parrotfish, surgeonfish, butterflyfish, etc— by eating the parasites and dead body tissue off their client's skin, fins and mouth. 

However, at reefs with damselfish, things are not always so peaceful.