The Hydor slim heater is a submersible aquarium heater for micro tanks and mini aquariums 2-5 Gallons. Ideal for use in mini aquariums for fish that require heated water for a long, comfortable and healthy life. Submersible heater for micro tanks and mini aquariums Plug-and-play installation Shock-proof heater provides natural warmth This safe, UL-listed aquarium heater draws only 7.5 watts and has a slim design to suit small, 2-5 gallon fish tanks. Use to heat your tank 5-10 degrees hotter then room temperature and keep your fish and plants comfortable and healthy.