The most common heater type in the hobby today is the submersible heater. When shopping for an aquarium heater, you will see that there are many different manufactures and many different price ranges. You will see many people state that their type is the best aquarium heater on the market. My advice is to do your research and go with the heater “brand” that has really great reviews. I will help you here with that decision also.
Submersible heaters are aquarium heaters that you fully submerge under the water. This type of aquarium heater is a great choice because it allows you to hide your fish tank heater behind decorations such as rocks or plants. This will give you a more natural looking tropical fish tank.
These types of fish tank heaters are usually housed in a watertight housing made of plastic, glass, or steel. This type of aquarium heater will usually have a temperature dial on the top and will attach to your aquarium with supplied suction cups.
Most submersible tropical fish tank heaters on the market today have an auto shutoff function that shuts the heater off when the heater is removed from the water. This is a great option to have on your heater because this keeps your heater from cracking or burning up when it is removed from the tropical fish tank or it is exposed to air during water changes or tank maintenance.