Aquatic Flat Heaters provide warmth for small tropical fish and are designed for glass or acrylic desktop aquariums at least 1 gallon in size, but less than 10 gallons. They are completely submersible, easy to install and efficiently warm aquarium water. Suctions cups are included so you can mount the heater to the bottom or side wall of the aquarium. Be sure to choose the appropriate size for your aquarium.