I've been using the "cage carpet" (I think it's by ZooMed?) for my garter and I've never had a problem with it.. He can grip it well and it's designed so that even in the wash you'll never find any loose ends..
It comes in different colours in sizes to fit standard size aquariums, from I think 5gal to 30.. It also comes in packages of two so that you can switch them off when one is dirty..