These interesting little creatures are Christmas Tree Worms. They are a type of tube worm that is fairly common in tropical coral reefs worldwide. They are filter feeders and eat whatever drifts by into their extended fans. The fan also serves as a gill for respiration. There are many fan colors and patterns. The fan on these particular worms were about an inch in diameter. If you approach them too quickly, they instantly retract down into their hole and cover the entrance.