The Repti Rapids Cascading Waterfall is an excellent addition to any terrarium. It has a natural look to it and the tranquil sounds produced by it are very soothing. The Waterfall will also add beneficial humidity to the terrarium which is a necessity for all high humidity tropical type reptiles. If water reservoir runs dry simply pour water into it and the waterfall will begin running again. If however the pump runs dry the Zoo Med's Micro Pump 104 can run dry for 30 days without any damage to the pump. Size: 11 1/2" Tall x 9 1/2" from corner out. 16" at the widest part of the waterfall base.