I bought an anemone the other day. When I got him he had what I thought was a small rock (less than an inch) stuck to the foot. I didn't think anything of it, and he didn't seem to want to let it go, so I just acclimated and released him with the rock attached . A few hours later he was on the move and left the rock behind. Turns out, that rock was an old hermit shell...what's more, there's something in it. It looks like a little red tongue, with some pinkish-white protrusions. He never sticks out more than a few millimeters and as soon as I move him, he sucks right back in. My first thought was a bristle worm, though I have never actually seen one in person, so I can't be sure. He doesn't seem to be causing any problems, and hasn't moved from his shell in the past 5 days.

Can anyone give me any clues based on my vague description? As I understand it, bristle worms are harmless to fish. If that's what he turns out to be, would it be safe to just keep him in there? Would there be any benefits/repercussions?

I'm fairly new to the SW thing and don't have a whole lot of knowledge about worms and other critters that can infest a tank. I appreciate any advice you can give me.

doesnt sound like a bristleworm. You'd know one if you saw one. other than that, i've not a clue without a picture.