The most popular fish in the Great Barrier Reef is the clownfish. Clownfish are small, colorful fish that live in coral reefs. They are popular with divers because they are relatively easy to spot and they are interesting to watch. Clownfish are immune to the stings of the sea anemone, so they often live in close proximity to these creatures. The clownfish benefits from the anemone's protection, while the anemone gets free cleaning and food from the clownfish.