I would say Cypress Mulch, but I have my negativity about it, as it can get under the snakes scales and such, When I tried to use it for my White Lip Python, when she burrows, it somehow got lodged in her mouth, which I took her to the vet and got some antibiotics which i've been giving her. I started using that Co-Co husk completely. I want to try the Flukers Repta Lawn as I think real grass would be neat, but im kinda worried about how youd actualy clean it, and then replant every month? because you cant cut the grass in a tank. lol