I want to say never touch bristle worms with your bare hands. Use tweezers. Their Bristles will release when touched and it's like fiberglass. They are a good part of the cuc to most. I personally do not like them. I remove every one I see. I don't like picking up a rock or move a coral and wonder if I'm going to grab a bristle worm by accident.
Look like "fireworms" a type of bristleworm you can find in the South Florida region and I'm sure in a lot of other places. Would probably recommend removing, they can sting and get fairly large if you let them. One of our members had an interesting tank where he had a ~6-8" fireworm as a main attraction