The Lifegard Aquatics Underwater River adds beauty and vital oxygen to your aquarium in a single motion. Powered by the included air pump, this fascinating decoration harnesses an endless stream of bubbles to simulate a running river. The air bubbles flow up from behind the attractive bridge ornament, improving oxygenation and water movement in your aquarium. The Underwater River installs in minutes, and comes with everything you need to create a breathtaking visual display. Based on the output of the included air pump, this medium size is recommended for aquariums up to 40 gallons.