Most polyps live in large colonies. They are eaten by a variety of fish and their senses help protect them against these predators.

Many animals eat jellyfish, including sea turtles and various fish. The jellyfish defends itself with its sting and this helps protect it from these predators. Humans can be stung by jellyfish and in some cases, this can be fatal.

Sea anemones always live near clownfish. It is thought that clownfish help clean the tentacles and also scare possible away predators, although sea anemones are not eaten by many animals, with the exception of the sea slug.