A waterfall is completely unnecessary in a bearde dragon tank. They can cause alot of humidity in their cage unless it has very good ventilation. It also will wind up being clogged up with food and dragon droppings, as dragons love to drag food all over the cage, and they do like to defecate in water, if they can get most of their bodies into the water dish. Best to keep the water falls for dartfrogs, chameleons and other humidity loving reptiles.
If you are planning to house more than one dragon together, it is best to house males with groups of females ( in a very large tank of course, 5'x3'x2' or similiar (ie 6'x2'x2', 4'x4'x2 etc) larger is always better. As problems can result in keeping many dragons together, especially if the tank isn't as large as possible, it is better to introduce males into female cages just long enough to have them breed several times then separate. You can introduce again every couple days to ensure she is gravid, but best to keep females separate from males, it prevents unnessecary stress on the females.
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PHLdyPayne