My adult male goes off feed in the winter, (last year I think it was about 5-6 months). You'll be fine just monitor his weight, keep your husbandry on point, and if he does start losing a substantial amount of weight take him to the vet.
As long as he's drinking and producing heated you should be alright. Keep offering food no more than once a week. For me, when mine refuses for a few weeks in a row, I give him a couple of weeks where I don't offer unless he acts hungry (he shows the same behaviors every time he is hungry so I know when he will refuse or not).
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