Clownfish for the most part do well in a reef tank if there is an anemone. They are very hardy and easy to keep, but some can pester corals especially if there is no anemone. Sometimes they will adopt soft corals like the colt coral without a problem, while others will harass LPS corals such as Elegance, Goniopora, and Hammer corals. When adding them to a reef tank it is better to add a small group of them. The Ocellaris Clownfish is probably the least problematic in the reef aquarium, while others like the Tomato Clown will bully others and should be added last when housing peaceful fish.