I am a teacher and I have a bearded dragon, Loki, as a classroom pet. Eventually the lizard needs to be in at least a 40 gallon tank because they can grow to be 2 feet long. Instead of building the minimum 40 gallon, my husband built a 90 gallon one! It measures 4 feet wide, 1.5 feet tall, and 2 feet long. Bearded dragons have to have a hot side with a basking light to digest food and a cool side to escape the heat. They also require UVB light to help prevent metabolic bone disease. We used an extension cored to wire in a light strip to hold the UVB light and a ceramic light fixture for the basking light. They are a prey species so it is best to have doors that open in the front so that they aren't being picked up from the top as if a bird was picking them up.
We used melamine for the walls and plexiglass for the viewing space. We sealed the edges of the box with silicon caulk. Attic vents were added to the top of the vivarium for ventilation.