I was wondering what the proper enclosure size is. Littlefoot is going to move from his 20 gallon tank to a tank that measures 36w x 18d x 21h. He is pretty small and could stay in the 20 gallon for a while yet. But my bearded dragon is going to move out of that bigger tank into a custom enclosure.

So what this boils down to is what is the ideal enclosure size for an adult BP?

I want to make a custom enclosure for my BP down the road a bit but figure this big tank should last a while.