Can my corn snake move into his vivarium?
That would be fine. I have always judged the length of the snake with the length of the cage and as long as there isn’t to much difference it should be fine. Corn snakes actually do better in smaller places b/c the tend to get scared and/or stressed in bigger areas. Normally full grown corn snakes don’t need anything bigger than a 30 gallon tall tank when it is full grown, but you could have it in up to a 50 gallon and shouldn’t have any problems. Good luck with your corn snake… They are such a wonderful pet!