He looks pretty healthy, but how big is he from head to tail and how much does he weigh in grams?
Can you post pictures of his setup and lighting as well for me to possibly get an understanding why he may not be eating too well before you or I jump to the conclusion of possibly burmation or a winter cool down.
As AHBD said they do tend to eat less amounts at this age compared to how they were when they were younger, so it could just be that.