If he's eating 3 fuzzies every 4 days, I'd suggest moving him up to 2 hoppers every 5-7 days. My female is 22-24 inches and she eats two hoppers every 5-7 days and my male is 28-30 inches and he eats the same. You are just shy of 6 fuzzies a week, so it is time to move to hoppers.
Peter