Dimart Sea Treasure Air Action Aquarium Fish Tank Ornaments Decoration Real motion air-driven ornaments provide entertaining action while aerating your tank. Diver floats while the treasure chest opens & closes revealing the treasure inside. Each ornament is made from a durable plastic resin that is safe for your aquarium. It also can provide places for nitrifying bacteria. Requires air pump & 3/16" tubing (not included). Pressure control valve recommended. Use your pressure control valve (not included) to adjust the motion and the volume of air. Fun to watch and entertaining for you & your fish.