Aqueon 100101230 Flat Submersible Heater, Black,7.5W, up to 3 gallon

Aquatic 7.5 Watt Flat Heaters provide warmth for small tropical fish and are designed for glass or acrylic desktop aquariums 1 gallon to 3 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. Do not operate or leave product plugged in when it is outside of water.