Hello I think you should only keep him in that tank for a small amount of time because they can not see the glass and can run into it . ! suggest a tortoise table, i have a male Russian tortoise and he is doing perfect in it.
I'm not sure if this was already posted, but no fruit and no squash for Russians, the tortoise table is great to help you with what to feed him. and my baby didnt eat good for a few weeks, I just kept offering him food and soaking and he eventually came around. I don't keep a water dish in his cage, and they can overheat, i kept my temps high a first, but lowered them to about 95 basking and 80 everthere else, that seemed to help also.
Good luck