Tennis ball size turbo snail. He keeps knocking off frags that aren't glued. Would be great for a FOWLR or tank without unglued frags.
Is there a puffer in there? That's the only fish I would think would be a problem. The weird thing is I haven't seen him since I posted this. I'll check every night because that's usually when I see him. Not sure how a tennis ball size snail could disappear like that! LOL!