Sometimes a pair lives together with a pair of shrimp which raises the question how they avoid a collision in the narrow burrow when they all dart in at the same time at the approach of a predator (Philippines).

 

This is what happens when a fish doesn't get cleaned in time. The parasite is now too big to be removed and this Creole Wrasse probably suffers greatly from it (Caribbean).

 

Clown fish are clumsy swimmers and brightly colored. They would be easy prey for predators. So they live in sea anemones which have tentacles studded with stinging cells that can fire tiny poisonous harpoons when something touches them. No predator dares to pluck a clown fish from among these stingers. But why is the clown fish not stung? Because it absorbs in its skin a chemical from the sea anemone which the anemone uses to prevent it from stinging itself when the tentacles touch. This chemical paralyzes the stinging cells so they don't fire their harpoon (Red Sea).