OK. Here are the creatures I know of that will do a number on the population of the bristle worms:
Most hawk fish, especially the long-nosed hawk
I believe some butterfly fish, use caution as some are not very reef safe
I know the coral-banded shrimp, purple/yellow/normal/whatever, and I think zyrus is being over paranoid about the eating corals thing. I wake up quite often to a nice chunk of bristle worm in my coral-banded shrimp's mouth and claws.
These worms are very good cleaners, but should be removed or destroyed once they get 3-4 in. in length. When they get that big, they start stinging corals and can really hurt anemones in their foot.