I have had my green carpet for almost 18 months now--he has never moved and never killed anything. He has been one of the easiest things in the tank to take care of, but he had grown to the point where I am either putting him in my other tank or trading him in soon--my tank is only 35g, but it seems to do well even now. From day one my clown has basically lived in it--even at night, he curls up inside the mouth and I always thought he was going to eat it, but never has.
