Answer: Clown fish can turn and dart quickly when they are about to approach coral reefs. The reason behind this is their caudal fins that allow them to swim slowly. Clown fish can also camouflage with the same color as anemone, especially at night. So basically, clown fish and coral reefs, especially anemone, work together. Clown fish feed the anemone when the fish cleans itself in it. And anemone provides protection and shelter for the clown fish.
Hope this helps!