First ball python, won't eat.

I would wait at least 5 days, and yup, a hopper should be the perfect size

Good luck :)

If your snake doesn't eat again in 2-3 days, you might want to consider cluttering up his tank. I had my baby bp in a 20g, she's a little over a foot, by maybe an inch. She wouldn't eat for me. It was suggested to switch her to a smaller tub, and as I was setting up the tub she started daytime roaming. I waited a week after switching her, bought a live mouse hopper, and dropped it in the tub. Walked away, came back and it was gone.

Hope you don't have to go through all that, but if he doesn't eat it's an option :) Good Luck!

A lot of ball pythons will not take frozen / thawed rodents. Try feeding a live hopper mouse, and leaving it in overnight.

Good luck.