The Uniclife 250 W Aquarium Preset Heater Submersible Tank Warmer is a great way to provide a comfortable environment for your fish. The heater features a built-in electronic thermostat that automatically heats water to 78 degrees Fahrenheit. The LED indicator on the heater will turn red and shut off automatically when the tank reaches 78 degrees. The heater is easy to install and requires only two suction cups to hold it in place.