What all do you feed him? Chameleons have been known to go on hunger strikes. They get bored with the same old food. A healthy adult can go a couple weeks without eating and survive believe it or not. How often do you give calcium with and without d3. He really should not have a calcium deficiency if you are giving him it on a regular basis. Can you post some pictures of him? If the two tanks are stacked, how do you get ventilation?