Aquarium Heaters

Heating Devices For Fish

An aquarium heater is a device that is used to keep the temperature of an aquarium above a chosen level. With the help of these heaters, you can keep a range of tropical fish in cooler climates.

Even in warmer climates a heater should still be used. This is because the aquarium water temperature can fluctuate with the difference between night and day. A fish's metabolism and respiratory systems work much better in such constant temperatures. Although a fish subjected to temperature fluctuations may not immediately die, they will live longer with a constant daily temperature.

Aquarium Heater Safety

Water and electricity do not mix so safety is paramount when it comes to aquarium heaters. Always use a submersible heating device designed for the aquarium or you may be risking your safety.

Never plug in an immersion heater before it is in the water. It will get got enough to shatter very quickly. For the same reason always wait 30 minutes after turning a heater off before removing it from the fish tank.

If you even see any condensation inside a glass immersion heater throw it away or return it immediately. If water can seep in the unit may pose an electrical safety hazard for you or your fish. Any style of heater showing deterioration of the casing should also be discarded as such devises are not safe to repair.

Varieties of Aquarium Heaters

There are many types of aquarium heaters but they can be broadly be classified as glass immersion heaters and under gravel heating. How it works depends on the particular aquarium heater but all use electricity which heats an element encased in a waterproof shell.

Glass Immersion Heaters

Most aquarium heaters belong to the immersion style of heating category. These heaters consist of submersible glass or stainless steel tubes that contains a heating element wound around a glass or ceramic insert.

Most modern immersion heaters are fully submersible. The thermostat control is placed at the top of the unit for easy access above the water. They have an adjustable thermostat that turns the heating element up or down to meet your desired temperature. The thermostats contain a bimetallic strip. In such devices strip contains two metals. The metals expand at different rates and this forms the basis of the thermostat mechanism.

When choosing an immersion heater it is important to know the volume of your fish tank. A given heater will be rated by how many watts of electricity it consumes. The larger the aquarium the greater the wattage required. If the difference between your room temperature and the desired aquarium temperature is large then this will also demand a higher wattage. Each manufacturer will usually have a recommendation on the packaging.

Such immersion heaters usually have a mark which must be covered by water for correct functioning. If left partially uncovered by water the heating device may overheat, killing the fish and damaging the heater.

After use for sometime a thick scale may develop. This hard mineral plaque can be safely removed using steel wool.

Some aquarium heaters are quite poorly made with elements that burn out after a few months use. This is one aquarium device that requires a better quality product if you are serious about your fish as heater failure often results in mortality.

Titanium Aquarium Heater

Aquarium heaters made with titanium elements are the reliable but expensive style of immersion heater. The element is virtually unbreakable, it is not going to shatter if bumped while hot. There is also no glass to shatter as the outer casing will be completely metallic.

The materials used also gives a titanium heater superior conduction as well as resistance to oxidization. The low reactivity makes these ideal heaters to use with corrosive marine aquarium water or less reactive fresh water.

When selecting a titanium aquarium heater make sure you have purchased an all in one unit. Some will have the thermostat separate rather than built in. Most aquarium keepers find the all in one style meets their heating needs best.

Undergravel Cable Heater

Aquariums can also achieve increased temperature via a flexible heating cable. These cables consist of an element coated in a thick flexible rubber. The cable can be buried beneath the aquarium substrate.

This type of heating is popular for planted aquariums. Heating the aquarium substrate allows a gentle flow of water through the gravel. Plants benefit by being able to uptake more nutrients from the circulating water.

Under Tank Heating or Heating Mats

Aquaria can also be heated using heating mats. These mats are placed beneath the aquarium itself. These mats are made up of a synthetic material concealing a heating element. This style of aquarium heater is generally not suitable for very large aquariums. They are useful when you have a series of smaller aquariums that are not large enough for an immersion heater.

Aquarium Heater Prices

There is traditionally a large mark up on aquarium heaters sold from pet stores. It is well worth looking for yours in our shopping facility where cheap aquarium heaters are more common.

Multiple Aquarium Heaters

Although one can be adequate their are advantages to using multiple aquarium heaters. Inevitably a heater has a limited lifespan and will break at some stage in the future. When this happens it can be catastrophic for temperature sensitive fish. If there are multiple heaters the remaining heater can take up some of the load while a replacement aquarium heater is purchased.

Multiple heaters in the aquarium are also practical when it comes to heat distribution. When the heat source is concentrated in one area an aquarium can develop hot and cold spots. This is especially the case in calm aquariums with limited water movement. Place an immersion heater at each end of a long aquarium where turbulence can not be increased.

Choosing the Correct Aquarium Heater Wattage

The strength of an aquarium heater is determined by it's wattage. The larger an aquarium is the higher the wattage will be required.

The other main factor in choosing is the difference between the room temperature and the heat you would like the aquarium water to be. As the temperature difference increases so to does the recommended heater wattage. The increase in wattage is not as steep in the larger aquariums due to the lower surface area to volume ratio conserving more heat.

This is just a guide as your own aquarium may vary somewhat. Factors such as lights and lids will impact on the heater strength required

Estimated Heater Size For The Different Aquarium Volumes & Heating Loads

Aquarium Volume
5ºC / 9ºF
10ºC / 18ºF
15ºC / 27ºF
5 gallon / 20 Litres 25 Watt 50 Watt 75 Watt
10 gallon / 40 Litres 50 watt 75 watt 100 watt
20 gallon / 75 Litres 75 Watt 100 watt 150 Watt
40 gallon / 150 Litres 200 Watt 150 Watt 200 Watt
50 gallon / 200 Litres 250 watt 300 watt 2 x 200 watt
75 gallon / 300 Litres 2 x 200 watt 2 x 250 watt 2 x 300 watt

Use these figures as a guide to choosing an adequate aquarium heater

All Products