Aquatic 5 Watt Flat Heaters provide warmth for small tropical fish and are designed for glass or acrylic desktop aquariums up to 2.5 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. Aqueon products offers a wide range of items so that you can build and maintain a healthy aquatic environment. All the essentials from fish tanks, filters, lighting, food, care, and other supplies that your pet fish needs.