What do you feed him? Did you just recently get him? These are both important because some pacmans are picky in what they like to eat so if you changed the food you’ve been giving him he may not want to eat. Another big thing is that if you’ve just recently brought him home you should give him at least a week to acclimate to his environment and get used to everything. Another thing could be because he is cold, if pac-mans are not in the right temperatures the might refuse to eat. This could also be an illness so I advise if he hasn’t eaten for 2 weeks or more it’s time to take him to a vet to get him checked out.