At that weight, I would be feeding small rats. you would have to feed 2-3 mice to keep him full.
Additionally, he can go a long time at that weight without food. If he refuses again, offer less often, and he will take a rat sooner than later.
Shayna hit a wall at about 900-1000G and started refusing meals and began winter fasts. Again, being a female, normal to be a little higher in weight when she began giving me issues with feeding. For a male, he seems at just that size.
Not all do it and he could just be having an off week, etc. However, don't be worried or surprised if he refuses for a bit.
Good luck!