I have 3 RTC, all around 8-10 inches. I am looking for ideas for big caves for them to lounge in while they are still on the younger size. I have been using big PVC pipe T fittings, but they keep quickly outgrowing them.....Any thoughts on something big, I could place in the tank, that doesn't look horribly ugly, that they won't out grow in the next 6 months? I really do not want to build rock caves, for fear of them redecorating and banging the rocks around on the bottom of the tank. I keep bare botton tanks, easier to clean. Thanks.