Aqueon Aquatic Flat Heater 5 Watts 

Aquatic Flat Heaters provide warmth for small tropical fish and are designed for glass or acrylic desktop aquariums at least 1 gallon in size. 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.

Features:

• Ideal for small glass or acrylic desktop aquariums with up to 2.5 gallons
• Can be used with glass or acrylic enclosures
• Warms aquarium water up to 6°F above ambient room temperature
• Suction cup included for mounting to aquarium