Are these bristle worms? This is just a few of them that I see in my tank. Should I keep them or toss them?. I'm also pretty sure I've got a much larger one hiding in the rock work. Thoughts?
Toss it. Looks like some sort of bristle worm to me. They are harmless but those bristles can be a pain in the donkey. I found that brittle/serpent stars make excellent competition for these guys.
Bristle worms. If it were my tank, I'd add it back to the tank, but each reefer feels differently about them. They have their pros and cons like many of the "hitchhikers" in our tanks.