I am going to have my son-in-law build a case to house two aquariums in...one for my baby corn, stalker and the other for my baby Mexican rosy boa, balboa. They will be one on top of the other with room for lighting, ect. I think there will be a cabinet below the cages and book shelves above them. I think the case will be my Christmas present, so I need to tell him what size aquariums it will be holding. Right now they are both in separate 20 gallon critter keeper aquariums. I am thinking long term....Would it be okay for them to each have a 55 gallon aquarium.... I would have plenty of hides, climbing things, etc. The 20 gallon aquariums would just sit in the case until they get bigger. Then I would replace them with the 55 gallon ones. Am I thinking to big? Would they feel safer in a smaller size? Please let me know your opinions so my son-in-law can get started building!! Thanks connie