isn't rock inert??? At any rate the tank was gonna have java fern and giant anubis anchored to the drift wood you see in the video with crypts being tucked in around the larger rocks. I have kept crypts with african cichlids, even veggie lovers like duboisi and they won't touch it. Once it started its runners going no one in the tank could move it, the cryps wrapped around the larger boulder bottoms in my tank. I'll have to start the tank with more plant friendly fish first then move to the big guys.