Nothing. Provided his environment is right (temps, etc), he'll start eating when he's ready.
He's a good sized male. He can probably go a full year without eating if he wants.
It sounds like he just skipped one meal. Just try again next feeding and get used to skipped feedings. You're gonna have a lot of them over the years.
Males don't need to eat a lot. Try feeding him something smaller once every two weeks instead of weekly. Even then, males just don't eat sometimes, even when you think they should.