Hmm, I haven't had problems with that. I have a naughty tank in my bathroom for bad rats, LoL, and they haven't chewed anything on it. But they aren't in it for more than 1 night at a time. I used to keep 3 girls in a 30 gallon, and they never chewed on it. I just give them all sorts of stuff to chew on; pig ears, dog biscuits, rawhide chewies, papertowel/toilet paper rolls, etc. They are kept pretty busy. At WalMart, by the checkouts, they have $0.88 dog toys that work well.