Aquarium Heaters – Making the Best Choice For Your Fish

Unless you plan to keep only cold water fish, you’ll need to choose an aquarium heater. Fish cannot provide their own body heat. This is often thought of as being “cold blooded,” but this is a misnomer. The temperature of these animals is directly related to the temperature of their environment. The ambient room temperature generally will not provide enough warmth for your fish, so you will need to invest in a proper heater. Maintaining a proper water temperature is an essential step in keeping your fish healthy. Most fish will need to be kept in water that is between 78 and 80 degrees Fahrenheit.

Aquarium heaters are available in different types based on how and where they supply the heat. Most heaters have a control which allows you to adjust the heat to the proper temperature and most contain a thermostat which keeps the temperature at an even level. Here is a quick look at your different options.

Submersible and Immersible Heaters

As the name implies, submersible heaters are made to be fully submerged in water. Immersible heaters are mostly submerged, however, the controls must remain above the waterline. Immersible heaters frequently hang from the back or side of the tank. Both submersible and immersible aquarium heaters are effective and relatively inexpensive. Because they are inexpensive, it is easy to keep an extra heater of this type on hand as a back-up in case your primary heater fails. Because at least part of the heater may show in the tank, these can be difficult to camouflage; generally submersible heaters are easier to camouflage than immersible heaters. These heaters may be made from glass, plastic, aluminum or titanium alloy. Some models can create “hot spots,” but in a tank where the water circulates well, this is generally not a problem.

Substrate Heaters

These types of aquarium heaters heat the water from the bottom up. These heaters are installed below the rock, gravel, sand, or other substrate material used in your aquarium. They provide heat that is more uniform than submersible or immersible heaters. Typically they are completely hidden by the substrate material, making them a very attractive choice. If you have an aquarium with live plants, this heater is a good choice as it promotes plant growth. These heaters are also the most popular style in Europe.

The drawback of this type of heater is that it is installed under the substrate. While it is easy to install such a heater when you are initially setting up your tank, if your tank is already established, it will have to be taken down to install or repair such a heater.

Filter Heaters

Filter heaters are one of the newest kinds of heaters available. These heaters consist of heating blocks that are placed inside the filter. This heats the water during the filtration process, providing even heating. These types of heaters are camouflaged inside the filter itself. These types of filters can be expensive and are not as common.

What? Watt!

Once you’ve chosen your heater style, you’ll need to know what wattage will be required to keep your aquarium at the right temperature. Generally, you should multiply the gallons of water your tank will hold by 5 to get the number of watts to purchase. For example, a 20 gallon tank would require a 100 watt heater. If your aquarium is large, you may wish to use more than one heater to provide the necessary wattage. For example, a 50 gallon tank requires 250 watts of heating power. Two 125 watt immersible heaters, one at either end of the tank, would provide the right amount of heating. The other advantage of using more than one heater is that in the event of a heater failure, the temperature in the tank will not plummet as quickly, giving you a little extra time to get another heater installed; when you have a considerable financial investment in fish and animals, this can be important.

Keeping an Eye on the Temperature

An essential part of the heater purchase is a separate thermometer. This will allow you to double-check your water temperature and make any necessary corrections, and to spot a heater thermostat that may be beginning to malfunction. Fluctuations in temperature can cause stress to your fish, undermining their health. Thermometers are available in several styles, from glass thermometers that float in the tank, to digital models that sit outside the tank.

Handling a Heater When Its Hot

If your heater has been on, turn it off and unplug it for a minimum of 15 minutes before you remove it from the aquarium. Otherwise the heater can crack from the change in temperature, or overheat. Even if you will not be removing the aquarium heater, it is a good idea to unplug the heater when you are working in the aquarium, changing the water, for example. Aquarium heaters are electrical appliances and electricity and water DO NOT MIX. Always use proper safety precautions. Make sure that the heater is properly submerged in water when it is in use, whether it is a style designed for complete submersion or only partial immersion; this means keeping an eye on your water level and replenishing the water in the tank as needed.