The Interpet LIFE THERMAL Flat Aquarium Heater is designed to increase the temperature of an unheated tank by 41°F. This 15 Watt compact heater can be used to keep tropical life and plants in any aquarium up to 5 gallons. It's the perfect choice for new fish keepers. The Interpet LIFE THERMAL Flat Heater can be fit anywhere in the tank: under gravel, in your filtration or on the side of the glass, it's completely up to you. The flat discreet design means that it won't distract from the look of the tank, no matter where its placed.