The Clownfish and the Anemone

Symbiosis means “living together.” When both partners are benefited, the practice is also known as mutualism. That’s the way it is between Mr. Clownfish and Mr. Carpet Anemone.

How does the relationship work?

The tentacles of the anemone are covered with stinging cells. When predators are attracted to enter in pursuit of the fluttering clownfish, they are stung, killed, and eaten by the anemone. The clownfish, in turn, feeds on the scraps of food from the anemone​—often even taking it from the anemone’s mouth.

But why isn’t the clownfish stung and eaten by its host, especially when the fish steals food from the mouth of its host?

Scientists have discovered that the clownfish’s immunity is not because the carpet anemone recognizes the services rendered by its tenant. Rather, a change in the mucous covering of the fish inhibits the discharge of the anemone’s venomous stinging cells. Mr. Anemone reaps benefits from the relationship, but Mr. Clownfish is the one that is in control of the operation.