I don't think there's too much! In fact you could probably add more. My cage, which is the same size as a 40 gallon breeder, is no where near the size of the Detolf, but I load my cage up as much as I can to provide tons of interesting things for my Syrain, Butters, to do. I want to think that the more he has to do and explore in his cage, the less he'll be bored and won't become destructive. Here's a video of everything I have in his cage.