I'm having a bristle worm problem in my reef I've seen good and bad things about the arrow crab. I picked one up and he is only maybe 2 inches from side to side (I know that's pretty small), and I was wondering if I will have a problem with him. I've got some slow-moving fish like a mandarin, cleaner goby, and a pink-streaked wrasse as well as hermits and some smaller snails. I've got the arrow crab in a smaller tank while I get more thoughts. What should I do?