Since most fish are cold blooded and will need heating to ensure that they stay alive and live comfortably, an aquarium heater then becomes an essential item in most home aquariums. If your unsure of the type of heater is required for your aquarium then your local pet shop or aquarium shop is the best place to ask. 84 degrees is the minimum requirement for most tropical fish so the type of fish, aquarium size and plants will determine the type of heater you will need.buy aquarium heater filters