Yes, he is pretty small. I have a male that weighs a bit more than him and is only a yr old. However, I actually had the same issue with my first ball pythons weight. He was 2 and only 400g. If possible try switching your ball python to weaned rats, they have a much higher protein content and his weight will jump right up. I’m not sure how much a bedding switch will help with stress levels, I’ve just always thought it seemed nicer for them. I’m not really sure. Haha. Did he originally take frozen thawed from you?