My problem is the opposite. Caulpera takes over my tank in a week if I dont cut it back constantly. Runt ignores it, and the fish i had that were nibbling it are all dead by his hand, well, raptorial appendage.
In fact, he switched burrows to a rock that had a lot of the macro growing on it. I'm guessing he likes the seclusion, or the view, or who knows.