Heats up to melt a pocket of ice around it up to - 20°F in outdoor ponds and tanks. Makes an opening in the ice to allow trapped toxic gases to escape safely and keep your fish healthy. Thermostatically controlled winter survival solution shuts off after melting the ice. Comes with a natural stone finish so it looks great in any naturalistic pond environment. Works on an energy efficient 300 watts and is UL listed for safety; includes 15 foot power cord. Help keep your pond ice-free with the Tetra Pond De-Icer. Designed as the perfect winter survival solution for fish, it heats up to melt ice around it wherever you place it in your pond. A layer of ice on your pond traps wastes and gases that are toxic to your fish. By melting some of the ice, it allows the trapped gases and toxins to escape and keep your fish healthy through the winter. Thanks to its natural stone finish, it looks great in any outdoor naturalistic pond environment. It works with temperatures as low as - 20°F, and has an energy efficient thermostat that automatically shuts off after melting the ice. Plus, it includes a 15 foot cord, works with 300 watts of power, and is UL listed for safety.