ZAP! That’s what happens to most fish who get too near an anemone. Anemones have tentacles that sting, which is how they stun their prey before eating it. The clownfish, however, has its own special layer of mucus on its body that keeps it from being stung. So the anemone makes a perfect home for a clownfish. By living among the anemone’s tentacles, the clownfish is protected from other fish that might eat it.

When it comes time to have a family, the male fish clears a nest on a patch of rock below the anemone. Usually the anemone’s tentacles hang over this nest to protect the eggs from predators. Once the female lays the eggs, the male fans the eggs and keeps the nest clean and safe. After an egg hatches, its larva swims to the surface and floats among the algae for about a week as it further develops. About eight to 12 days after hatching, it returns to the bottom to find its own anemone to live in.

Finding an anemone home isn’t easy. Most anemones are lived in by a male and a female clownfish and several “males in waiting.” What are all those boys waiting for? They are waiting for something to happen to the female. If the female dies, her male partner becomes the new female, then the next biggest male becomes the new man in charge. The other males continue to wait and fight amongst themselves, with the bigger fish chasing and attacking the smaller fish. Since these males in waiting spend so much time chasing and fighting, they don’t have as much time to feed. When they can’t eat, it is hard for them to develop and get bigger. Normally, the smallest clownfish is kicked out of the anemone.

What does the anemone get in return for protecting the clownfish? Well, because the clownfish really likes to protect its territory, it drives away other fish that might be harmful to the anemone. Also, it keeps the anemone clean. Any particles of food the clownfish drops become an extra snack for the anemone. When two animals live together each of them can gain something from the other, this is called a symbiotic relationship.