Penn Plax Aerating Action Ornament, Tropical Clam &ndash; Opens and Closes AIR DRIVEN ORNAMENTS BRING ANIMATION TO YOUR TANK: the real motion air driven ornaments movements provide fun and entertaining action while aerating your tank. CLAM OPENS AND CLOSES WITH THE STEADY STREAM OF BUBBLES: the clam top rises and falls with the bubbles to reveal the treasured pearl inside. PROVIDES MUCH NEEDED AERATION FOR YOUR TANK: bubbles escape the clam to provide your tank with much needed air. Requires air pump and standard 3/16 tubing (not included). MADE OF FISH SAFE AND DURABLE MATERIAL: the Penn Plax Aerating Tropical Clam is made from a durable plastic resin that is safe for your freshwater and saltwater / marine tank. SHOP PENN PLAX FOR ALL YOUR PETS NEEDS: continue to customize your aquarium with Penn Plax Action Ornaments and other decorations and dcor.