Last Tuesday I got my first Russian tortoise. I got him from Petsmart and he looked health when I got him. I have not been able to get him to eat anything so far and he's been burrowed since Thursday. If I un-burry him he hisses at me and immediately burrows back in. I read somewhere that maybe his cage wasn't light enough inside so I added another light. I have 4-5 inches of coconut husk/sand as the substrate and a power sun 160 and a fluorescent uvb for additional light. Any suggestions? Should I be worried or do you think he just needs more adjustment time? Thanks!