How do clownfish survive among sea anemones without getting stung?

Sea anemones have stinging cells called nematocysts, but clownfish can live safely among them because of a protective mucus coating on their bodies. That mucus reduces the chance that the anemone's stingers will fire. Clownfish also seem to acclimate to their host anemone by rubbing against it gradually, which may help them avoid being treated as prey. In return, clownfish can clean the anemone and attract prey with their movement. This relationship is a classic example of mutualism.