Yup coco fibre, he has a bathing area but really lives to dig rarely sitting in one hole more then a few hrs before starting a new one lol I fill them in a few times a week. I looked at an all water set up but I would need the filter system and am not big on the constant sound of a mini waterfall (drove me nuts as a kid) I'm sticking to what I got. I'm grabbing a higher container tomorrow he's just gotten so big so fast.