Aquariums are tricky for chams. The only smaller species that have been maintained in aquariums long term are the "pygmy" or "leaf" chameleons of genus Brookesia and Rhampholeon. These are mostly understory or leaf litter species. The arboreal chams (veileds, panthers, most more familiar ones we keep) just don't thrive in them unless they are very tiny hatchlings on a temporary basis. For info on the leaf chams go to www.adcham.com, www.chamresearch.com, or the good commercial site www.calumma.com. Most are wc and very delicate to treat for the usual parasites and diseases. They are usually small, only a few inches total length.