Bristle worms are GOOD & BAD. Good because they do what nature intended they scavange! Eat up extra food that hits the bottom. They are bad because THE REALLY big ones eat ALOT !!!! sometimes maybe even munch on things they're not supposed to. Plus I have a bad reaction anytime I touch one of them accidentally.
My fingers swell and I get small hives and my fingers kinda go surface numb for about 24-48 hours. Not a big deal just aggravating.
Anoher reason they are not my favorite scavanger in the tank. If you have an over abundance of them you are probably feeding them instead of your target fish or other.