bristleworms are more important, imho, if you have sps (branching stony, mostly) corals, which have very tiny mouths. I'm sure they'll arrive on some specimen, but don't worry about their lack at first. I lost all mine, swore I had none, and now I see about 4 larger ones (up to 5-10 inches) and a number of little guys, ironically, close to what I had before I moved house. They're great detrivores and are good to have, but just let them show up.