Randy,,don't fill the holes with cement,you don't know what effect it'll have on the water or frog.you don't need plants,fake ones might even hurt your frog.you have to cater to the needs of the frog,not really what you want.he doesn't need to hide,but still take "amphibian precautions" ,,i.e...like put him in a low traffic area,maybe where a cat won't stare at him all day.and use cardboard and box in the sides and back of the tank.a bullfrog isn't called that for nothing,but can still fall under stress.being so raucous and responsive,they make interesting pets,have real personalities..but are demanding....