They do pump their legs and head to breathe. What are your 4 temps now? Basking, warm side, cool side and night. How are you achieving these. Heat pads can get too hot and burn tortoises. I use them, but attach them to the wall of the hide rather than floor. What are you feeding? He might be settling in still, but if he is getting too cold, he may be getting sick. Are there bubbles or discharge from the nose? Is his breathing audible?