Fluctuations in water temperature will occur in the majority of wild fish habitats and do not cause health problems or distress to fish or invertebrates. Providing these are naturally occurring fluctuations within an acceptable range, they are simply part of life in the wild. However, in captivity, it is difficult to precisely emulate these naturally occurring habitat phenomena. Also, some tropical fish come from exceptionally warm waters which will need to be provided within the aquarium environment. This is where an aquarium heater comes in, warming and maintaining the aquarium at a stable temperature.

3 Best Aquarium Heaters

In case you are looking for a quick answer to your search for the best fish tank heater, we have provided our top three below. All three of these aquarium heaters will provide accurate and effective heating for your fish tank. The Hygger and AQQA heaters however have an external LCD screen for very easy control. While an aquarium thermometer is always a good idea to double check the temperature, the thermostats on these heaters are very accurate!

Role and Benefits of an Aquarium Heater

If you are an aquarist with a special interest in saltwater aquaria, then these tropical fish will inevitably be from very warm environments in the wild; thus requiring a suitable aquarium heater. It is not only fish, but other living organisms such as soft coral like pulsing xenia, and SPS and LPS coral which will need to be kept within a strict temperature range to survive and thrive.

Consequently, the majority of home aquaria and tropical fish tanks will need to be heated. This is in order to provide a stable temperature range and consistent habitat. 

An aquarium heater aims to raise water temperature to a pre-set level and then to keep it within range. This should be a straightforward and safe process. We are therefore looking at aquarium heaters which are reliable, easy to use and accurate. 

There are hundreds of aquarium water heaters available for purchase nowadays. To help you choose wisely, we have endeavored to test and study the features of a wide range of heaters. This research has culminated in our 10 best aquarium heater suggestions for safe and effective function.

Table of Best Fish Tank Heaters

Types of Fish Tank Heater 

To make an appropriate choice for your fish tank environment, you need to understand the different types of aquarium heaters that are available for purchase. The four basic groups are:

  • Submersible Heaters
  • In-Line Heaters
  • In-Filter Heaters
  • Substrate Heaters

Submersible Heaters

As expected, submersible heaters are placed beneath the water line. Apart from needing to be fully submerged, they can be placed in a position to suit the aesthetics of the aquarium. They are efficient water heaters by design. This is a common type of aquarium heater. The heating element is usually housed within a glass tube which is placed within the water column

In-Line Heaters

An ‘in-line’ is an external aquarium heater which is located on the outflow of your fish tank filter. The water is heated as it flows back into the aquarium on its return journey. These heaters are discreet and don’t take up room within the aquarium, but remain efficient in temperature regulation. Another advantage is that they avoid your fish coming into contact with the heater.

In-Filter Heaters

As the name suggests, In-Filter heaters are located within the filter itself. When you buy your filter, you can opt for one that combines with a built-in heater. This is certainly convenient, but you will need to ensure that it successfully heats to the required temperature.

Substrate Heaters

Substrate heaters are more widely used in the UK and Europe than in the United States. The heating wires are incorporated within the gravel or substrate of the aquarium – a bit like under floor heating! This heating method is particularly advantageous within planted aquaria where the aesthetic value of the flora is especially important. Whether you have sand substrate or gravel substrate, this type of heater will be equally suitable.

How To Choose the Best Aquarium Heater

Match the Heater Type to the Needs of Your Aquarium

You will need to carefully match your heater choice to the needs of your aquarium. Depending on your interest – whether you have a reef tank, a saltwater or freshwater aquarium – you must ensure that the heater type is suitable. Some aquarium heaters, however, are generic and can be used in the majority of fish tank environments.

Manufacturers do try to give clear guidance and instructions. We strongly suggest that you adhere to the guidelines provided. 

Match the Heater Type to the Size of Your Aquarium

Inevitably, power and output levels of different heaters will vary. Ensure that you know the size of your aquarium; in order that you can purchase a heater capable of heating a tank of the water volume you own. 

Again, the manufacturer will clearly state the tank size and water volume that can be readily heated by the model of heater being sold. Read the guidance carefully to ensure that you make a responsible choice. 

Budgetary Considerations

The price of aquarium heaters can vary enormously. The top end of the range can prove to be a very costly business. So don’t be tempted to purchase a heater more powerful that you actually need for your aquarium environment. 

As with any purchase, a higher price doesn’t necessarily positively correlate with better performance. Conversely, there are some extremely cheap options that will present a maintenance nightmare; with potentially harmful consequences to your aquarium environment and fish stock. 

With careful consideration, there are some competitively priced aquarium heaters on the market that are efficient and safe. These offer excellent value for money – so choose wisely!

Maintenance of Your Aquarium Heater

Maintenance of your aquarium heater is an extremely important aspect of fish tank maintenance and fish health. A faulty aquarium heater can result in dire consequences for your fish stock. 

Water that is allowed to reach beyond acceptable limits in either direction, too hot or too cold, can be extremely damaging to fish health. You will need to regularly clean your heater. We do this at the same time as cleaning the filter, the substrate, decorations and the glass, as part of general tank cleaning and maintenance. Ensure too that the heater thermostat remains in accurate working order.

How Powerful Do You Need Your Aquarium Heater To Be?

This decision will be based upon a combination of factors. The first, and most obvious and indeed important, is the size of your aquarium. You will also need to consider the ambient temperature of the room in which you keep your tank. Climate fluctuations in the area you live, and how warm you like to keep your home or fish tank room is important. Whether your aquarium is located near an external wall or door, should also be factored into the process of heater selection.

The output or power of an aquarium heater is measured in watts. For a home aquarium that is kept in a room with a relatively stable and warm temperature, an appropriate aquarium heater size is calculated at 5 watts per gallon of tank water. This is just a rough guide and will vary depending upon how much higher than room temperature you need the water to be for the fish you own (see table below).

If you own a very large tank and/or it is kept in a colder area of the house or room then this must be factored into your decision. Some aquarists recommend two heaters at opposing ends of the tank to ensure a more consistent temperature throughout the volume of water.

As we have stated before, read the manufacturer’s instructions and recommendations carefully. All heaters are different, and the manufacturer’s notes should guide you. 

Size of Aquarium in Gallons

Watts required to keep water temperature at 5, 10 or 15 degrees Fahrenheit above room temperature.

5⁰F

10⁰F

15⁰F

5 Gallons

50

50

50

10 Gallons

50

50

100

20 Gallons

50

100

100

30 Gallons

100

100

150

55 Gallons

150

150

200

75 Gallons

200

200

250

90 Gallons

200

250

300

Best Aquarium Heater Reviews

Hygger Aquarium Heater for Freshwater and Saltwater Aquaria

Hygger Aquarium Heater with External Digital Display
  • 【Quickly Heat Up】Voltage 110-120V/60HZ, power 300W, US three-pin plug, heater rod length 7.7 inch. Fast heating up aquarium heater, it takes about 3 minutes to heat 3.5 gallon water up 3℉
  • 【Auto on and off 】Reliable submersible aquarium heater. It will stop heating when the water temp reaches to the set temp, please note that the water temp may go up 1℉ more because of the waste heat. When the water temp is cool down to 1℉ less than the set temp, the tank heater will restart heating
This aquarium heater by Hygger is a well-made, fully submersible model which has an external digital temperature display. This external temperature display is brilliant and a huge advantage – no more struggling to see the dials!

With this heater model, there is an option of two output levels: 300 Watts for tanks between 30 and 60 gallon water volume, and 500 Watts for tanks between 60 and 120 gallon water volume.

This heater is a discreet design. The durable black plastic heater element guard is unobtrusive and easily hidden within your tank. The suction cups for placement of the heater within the tank are robust and well made. You should therefore be able to relocate the heater if you change your mind about its position.

Cobalt Aquatics Flat Neo-Therm Aquarium Heater – 25 to 300 Watts

Cobalt Aquatics Flat Neo-Therm Heater with Adjustable Thermostat
  • Super-flat design. Fully submersible, modern design for energy efficient Aquarium and terrarium heating. Includes reversible holster/bracket, which allows heater to face inward or outward. See the product images to determine the best neo-therm size for your tank.
  • Accurate, one-touch system. Simply set temperature between 66-96°f with one touch and the neo-therm electronic thermostat will maintain Tank temperature within +0.5°F. Led displays both set temp and actual temp, simultaneously.
  • Ultimate safety and reliability. Integrated thermal protection circuitry prevents heater from overheating. If you forget to turn it off, the neo-therm will automatically shut it down.

This Cobalt Aquatics aquarium heater comes in a great range of outputs to cover the needs of most tank sizes. From 25 Watts through to 300 Watts, this fish tank heater will provide for tanks ranging in size from up to 6 gallons through to 100 gallons.

This heater is fully submersible; our favorite design of aquarium heater. With its modern, flat design this heater can be discreetly placed within the tank.

Cleverly designed with a reversible bracket, this fish tank heater can easily be installed within the aquarium environment. 

One important safety feature of this aquarium heater is that it is shatter proof. It is not made of glass, but made using resin and thermoplastic. It comes with an outer casing which is also shatter proof. This is very reassuring to the aquarist as it poses no danger to your fish.

Another safety feature that this submersible heater boasts is an automatic shut off system together with thermal protection security. In combination, these avoid problems and dangers associated with an episode of overheating.

It features an easy-to-read LED display screen. This screen shows the desired temperature you have set for your tank together with the actual current water temperature. So you can easily keep tabs on any fluctuations and discrepancies in water temperature.

With a three year warranty, you can feel secure in your purchase.

AQQA Aquarium Heater

AQQA Aquarium Heater with LED Temperature Display
  • 🔥SAFE& DURABLE: Made of heat-resistant quartz glass and PC plastic cover, double seal material, providing explosion-proof, shatterproof, IP68 waterproof, much safer for human and your lovely fishes, your pets will no longer fear the winter
  • 🔥INTELLIGENT AUTOMATIC HEATING: Automatic constant temperature function, design with External Temperature Controller, Temperature Range is 68℉-93℉(20 °C-34°C), hold down the "+""-" set button at the same time for 5 seconds, switch easily from Celsius to Fahrenheit. It will restart to heating when the water temp is 1℉(1° C ) off the set temp. If power is shut off, the heater will keep the temperature settings until it powers on again

Another quality submersible aquarium heater, suitable for use in both saltwater and freshwater aquaria.

Available in five power options from 100 to 800 Watts to cover a broad range of tank sizes, as follows :-

  • 100 Watts for tanks with a capacity of between 25 and 35 gallons
  • 200 Watts for tanks with a capacity of between 45 and 80 gallons
  • 300 Watts for tanks with a capacity of between 80 and 95 gallons
  • 500 Watts for tanks with a capacity of between 65 and 135 gallons
  • 800 Watts for tanks with a capacity of between 80 and 220 gallons

This quartz glass model comes with an external temperature control panel, making it so much easier to manage the water temperature. The quartz glass is shatterproof; providing protection against harm. 

The LED Temperature Display shows you the current water temperature and your chosen temperature setting. This allows you to see any disparity between actual and required water temperature.

This aquarium heater will maintain a constant temperature within your tank. As soon as the water temperature drops by 1 degree below your selected temperature, the heater will recommence operation. So you can rest assured that your fish will experience no perceptible fluctuation in temperature. This gives great health benefits to your fish stock.

This AQQA aquarium heater comes with an adjustable hanging rack and two suction cups. Everything you need to expediently fix the heater successfully within your fish tank.

Hygger Shatterproof Titanium Fish Tank Heater

Hygger Shatterproof Titanium Fish Tank Heater

  • This fully submersible fish tank heater maintains proper temperature for your fish in a safety way, auto shut off when over-heats, resets when it cools down. The heater will shut off when removed from the water, and resume functioning upon return
  • Build-in external temp controller, easy to read LED digital number shows real time water temperature and set temperature. Indicator light let you know when the heater is on. It will be red when heating and green when the proper temperature has been reached
  • Corrosion resistant, shatterproof titanium tube construct heats fast, nearly unbreakable for both saltwater and freshwater aquariums. ABS plastic protective sleeve prevents fish from being scalded

This high end aquarium heater is a 500 Watt Model with the ability to reliably heat aquaria ranging in capacity from 60 to 120 gallons, and is straightforward to use.

There is also an 800 Watt Model available from this supplier which is suitable for tank capacity between 120 and 180 gallons (this is obviously a larger unit).

It features an external control panel; this clearly indicates both the water temperature that you’ve selected and the current actual water temperature. The water temperature can be set between 70 and 94 degrees Fahrenheit. The idea of an external control panel is excellent;  you can adjust your temperature setting without having to plunge your hands into the tank water. The LED display is clear and easy to read, making this easy to manage.

The heater rod itself is not too cumbersome, measuring approximately 8 inches in length.

Built to last, this model comprises a titanium heater tube housed within a plastic sleeve which affords protection to your fish – avoiding them making direct contact with the heat source. The tube is also shatter proof and won’t corrode – providing you with obvious safety benefits.

A reassuring safety feature is that the heater shuts off automatically as soon as the required set temperature is reached. Conversely, as soon as the water temperature then drops below your set temperature, the heater will be automatically reactivated. This ensures that the water temperature within your aquarium remains consistent; this will directly contribute to the health of your fish stock and your live planting.

Please note : Ensure that the heater is fully submersed in the water, and always unplug it before any water change.

Finally, this good quality heater is equally suitable for both saltwater and freshwater aquaria.

Hygger Titanium Aquarium Heater 

Hygger Titanium Aquarium Heater with External IC Thermostat Controller
IC temp controller can show the water temp and set temp at the same time, and there is a indicator light to show the heating status. Very easy and reliable to use, it will keep the water within 1℉ of the set temp.

Yet another fish tank heater from Hygger, this model offers lower powered units suitable for smaller tanks while still offering the same high standards of function. Made from titanium which resists the corrosive effects of sea water, this unit is suitable for saltwater and freshwater aquaria alike. Titanium is also shatter proof, an obvious advantage in such a sensitive environment.

This heater from Hygger comes in four different wattage/power options :

  • 50 Watts for small tanks with a capacity of between 5 and 10 gallons
  • 100 Watts for tanks with a capacity of between 10 and 25 gallons
  • 200 Watts for tanks with a capacity of between 20 and 45 gallons
  • 500 Watts for larger tanks with a capacity of between 60 and 120 gallons

If the ambient temperature in the room where you keep your aquarium is less than 50 degrees Fahrenheit, it would be appropriate to invest in a higher wattage model.  

You can set the temperature to any point between 32 and 104 degrees Fahrenheit via a central control module. Your temperature selection and the current actual temperature of the water are clearly displayed on this central control module. The LED display is large and easy to see.

A benefit of this model is the very precise thermostat. With an accuracy margin of within 1 degree Fahrenheit, you will be able to precisely control the heating of your aquarium.

The separate accurate thermometer which is provided with this heating unit attaches to the control module. The thermometer can detect temperatures from minus 68 degrees to 140 degrees Fahrenheit. It also provides a high degree of accuracy – to within 0.2 degrees Fahrenheit, which is very reassuring. Locate the thermometer at the opposite end of the tank to the heater. This will give you a more accurate idea of the general temperature within the tank once the heated water has been circulated.

It’s in the more expensive range, but is a reliable, easy to use, efficient heater.

Boxtech Submersible Thermostat Controlled Aquarium Heater 

Boxtech Aquarium Heater with Heat-Resistant Quartz
Fully Automatic Control: Design with External Temperature Controller, Temperature Range is 68 ºF-90 ºF, when water temperature achieve the setting temperature, heater will automatically stop heating, when water temperature is lower than the setting temperature, heater will automatically start heating
This compact, discreet and fully submersible heater by Boxtech is best placed in a vertical orientation within the aquarium. It is suitable for both saltwater and freshwater aquaria, so can be used if you’re a reef tank enthusiast. Fixation to the interior of the aquarium is via suction cups.

In order to ensure an even distribution of heat throughout the tank, place the heater as close as possible to your filter intake or outflow; or close to a powerhead. 

This aquarium heater comes in three different wattage/power options to cover the majority of home aquarium needs.

  • 50 Watts for small tanks with a capacity of between 5 and 15 gallons
  • 100 Watts for tanks with a capacity of between 10 and 30 gallons
  • 300 Watts for larger tanks with a capacity of between 30 and 80 gallons

The temperature control unit of this heater is external to the aquarium. This makes it extremely convenient and easy to use. The temperature can be adjusted to any setting between 68 and 90 degrees Fahrenheit, suitable for the majority of home aquaria; with the exception of those tanks which accommodate specialist fish requiring higher temperatures to thrive.

When the water in the aquarium has reached the temperature set on the control unit, the heating unit will shut off automatically; this will avoid the occurrence of any overheating.

The manufacturer makes a couple of recommendations. Firstly; to regularly remove any build up of scale that may collect on the unit; as this can negatively impact the heater’s temperature sensing system. Secondly, to turn off the heater and allow 10 minutes to cool down before removing it from your aquarium when you wish to clean your tank or change the water.

Salute Submersible Auto Thermostat Aquarium Heater 

Salute Submersible Auto Thermostat Aquarium Heater
Accurate Temperature Control: The aquarium heater temperature can be adjusted automatically. It is very easy to adjust the temperature you need, Adjustable heater from 68°F to 93°F (20°C - 34°C). A good temperature range for most fishes is 76°F to 80°F (25- 27°C).

This is a low priced aquarium heater available in four power options to cover a broad range of tank sizes, as follows :-

  •  50 Watts for tanks with a capacity of between 10 and 20 gallons
  • 100 Watts for tanks with a capacity of between 20 and 45 gallons
  • 200 Watts for tanks with a capacity of between 45 and 75 gallons
  • 300 Watts for tanks with a capacity of between 75 and 115 gallons.

Very easy to install. Simply attach the heater in a vertical position to the side of the aquarium using the two suction cups which come provided with the unit. This heater cannot be installed in a horizontal fashion.

This aquarium heater by Salute is suitable for all types of aquaria, both freshwater and saltwater. 

Adjusting the thermostat is a simple process – simply turn the dial located on top of the heater unit. The temperature can be set from 68 to 93 degrees Fahrenheit, which will accommodate the needs of the majority of aquarium fish.

The design features double waterproof protection so that the heater does not damage itself. With polarity prevention, the power conversion is safe and reliable which provides further protection. The glass tube is made from high temperature resistant explosion-proof quartz which provides safety for your fish.

The company, Salute, if confident that you’ll be happy with your purchase. For your peace of mind, they offer a full money back guarantee if you are unhappy in any way with the heater. Salute state that they will offer you either product replacement or full refund. 

Eheim Jager Aquarium Thermostat Heater

EHEIM Jager Aquarium Thermostat Heater, 250-Watt
  • Fully submersible
  • Thermo safey control protects agianst running dry. Will automatically turn off when water level dips too low
  • TruTemp dial recalibrates the heater for percise temperature regulation
  • Made of shock resistant and shatter proof glass for fresh or marine water
  • On/Off indicator light for at a glance monitoring
A fully submersible aquarium heater, for use in both freshwater and saltwater aquaria, ensuring a consistent water temperature throughout the tank.

The heater has a glass jacket which creates a larger surface area to give a greater dispersion of heat within the tank. The glass used in the heater is shatterproof for safety. 

The temperature can be set from 65 to 93 degrees Fahrenheit to within a precise accuracy range, which will cover the majority of home aquaria. A simple indicator light shows when the heater is functioning. The unit comes complete with a mounting bracket and suction cups for ease of installation.

Please note that this heater is quite long, measuring approximately 22 inches in length. This could pose a problem for smaller tanks as it is a fully submersible heater and must be installed below the water line.

Orlushy Submersible Fish Tank Heater 

Orlushy Submersible Fish Tank Heater with Adjust Knob Thermostat
★Precise temperature dial from 68 to 89°F allows for complete control of aquatic climate within a 1-degree difference.
★Adjustable Aquarium Fish Tank Water Heater Sensitive and reliable thermostat maintains uniform temperature. Automatic shut off when the temperature is reached

With four power options to choose from, this submersible aquarium heater by Orlushy represents very good value for money.

Power options offered are as follows :

  • a 100W model suitable for aqaria ranging in size from 15 to 30 gallons 
  • a 150W model suitable for aquaria ranging in size from 30 to 50 gallons
  • a 200W model suitable for aquaria with a capacity between 40 and 60 gallons
  • a 300W model suitable for tanks with a capacity between 50 and 80 gallons. 

Powerful and accurate, this submersible heater is made from 2mm thickened quartz glass. Safety features include a design that is shatterproof; so important in preventing dangerous glass shards contaminating your aquarium in the event of an incident.  

The thermostat of this model of heater is very accurate. This fact will enable you to keep a stable temperature within your aquarium. 

Once the water temperature in your tank reaches the required level, the automatic shut off feature will kick in to turn off the heating. The sensitivity of the thermostat will ensure that the heater will reactivate as soon as the water temperature drops below the required range. You will know when the heater is in active mode; this model features an indicator light which will switch itself on when the heater is in action.

It will therefore be very easy to maintain a consistent and appropriate water temperature within your aquarium. However, just to be sure and for your peace of mind, this heater comes with a thermometer; so that you can readily check the temperature within the tank.

A dial located on the top of this heater allows the water temperature to be set within a range from 68 degrees to 89 degrees Fahrenheit.

This model of heater is versatile. With the flexibility to be installed either vertically or horizontally, you will easily find a suitable and unobtrusive place within your aquarium to house this unit.

It is suitable for use in both saltwater and freshwater aquaria; so will be equally at home in your reef tank or standard freshwater aquarium.

ViaAqua Quartz Glass Aquarium Heater 

Sale
ViaAqua Quartz Glass Submersible Heater with Built-In Thermostat
  • High quality quartz glass
  • Fully-submerisble
  • Visible temperature setting
  • For use in fresh or saltwater aquariums

An affordable but effective aquarium heater by ViaAqua, this model is a fully submersible heater. It is extremely competitively priced, and provides a solid option for a relatively small investment.

This is an adaptable unit suitable for both saltwater and freshwater aquaria. This model is easy to set up and use. It boasts a straightforward installation process and clear settings. It comes with two suction cups provided to allow you to secure it firmly in place within the aquarium.

A red indicator light comes on when the heater is actively in operation; turning itself off once the required water temperature has been reached and the unit has been temporarily switched off. When the water temperature drops, the red indicator light will come on once again to show you that the unit is actively heating the tank.

This heater comes in four different wattage options :

  •  50 Watts for tanks with a capacity of up to 13 gallons
  • 100 Watts for tanks with a capacity of up to 25 gallons
  • 200 Watts for tanks with a capacity of up to 50 gallons
  • 300 Watts for tanks with a capacity of up to 80 gallons.

An indicator light shows when the model is actively heating your aquarium, and the temperature is clearly shown on a large display at the top of the heater. 

The temperature can be adjusted using the thermostat dial found at the top of the heat above the temperature display.

We must point out though that, given the relatively small price tag associated with this heater, the temperature settings may not be as accurate as some of the more expensive and sophisticated models on the market. 

Best Aquarium Heater – Our Recommendations

Naturally, choices and recommendations will depend upon your available budget. That said, all of the heaters in our Top 10 Best Aquarium Heaters list offer good value coupled with reliability and efficiency.

 If you’re looking for a lower priced aquarium heater, then you can’t go far wrong with the Orlushy Submersible Aquarium Heater. As the name suggests, this model is a submersible heater which can be installed either vertically or horizontally. It offers four power options; suitable for smaller aquaria from 15 to 30 gallons, increasing incrementally up to tanks of 50-80 gallon capacity.  

Whether you own a standard freshwater aquarium or a saltwater reef tank, this heater is suitable for use in both.  

This model incorporates good safety features. Made from 2mm thickened quartz glass, the design is shatterproof. The automatic shut off feature ensures the heater switches off once the required water temperature has been reached. This avoids the serious problem of overheating.  

The thermostat is very accurate. This will enable you to maintain a stable temperature within your aquarium. 

This is an effective, safe and easy to use aquarium heater which is competitively priced. 

For those of you with a slightly higher budget or a larger capacity aquarium, then you couldn’t go far wrong with the Hygger Titanium Aquarium Heater. This is also a submersible aquarium heater. This model has a very precise thermostat. With an accuracy margin of within 1 degree Fahrenheit, you can precisely control the water temperature within your aquarium.

The water temperature can be set anywhere from 32 to 104 degrees Fahrenheit. Both your chosen temperature and actual water temperature are displayed on a central control module. This has a very clear LED display, making it easy to check your temperature.

There are four different power options to choose from; catering for small tanks of 5-10 gallons through to large tanks of 60-120 gallons.

This heater from Hygger is powerful, safe and accurate with many popular features and attributes.

Whatever your budget and tank considerations, there will be an aquarium heater within our Top 10 Best Aquarium Heaters list that will suit your purposes. All are capable of reliably maintaining your aquarium temperature in order to provide an appropriate environment for your fish stock.

Aquarium Heater Installation Tips

Most manufacturers supply detailed instructions on installing and maintaining your new aquarium heater. We advise that you read and follow these carefully. 

That said, the following tips should guide you through and help you avoid pitfalls and problems. Do not add your fish to the aquarium until you reach the end of the following steps and processes.

Having received your new aquarium heater, check thoroughly for obvious damage. Better to return any damaged unit to the manufacturer straight away. This avoids negating any warranty that comes with your heater. It also avoids all the inconvenience of installing your aquarium heater only to notice that something is amiss. In particular, look out for cracked heating elements, broken or exposed wires, or broken plastic component parts.

Before attaching your heater using the attachment method provided, thoroughly clean the area of tank glass where you intend to place your heater. Often suction cups are used to secure aquarium heaters; these adhere to the glass more securely if the area is clean and algae free.

Your aquarium heater should not be close to aquarium plants, live or fake, or to any tank decorations. Clear the area before attaching your heater.

Install your heater in the correct aspect. Some aquarium heaters can be installed either  vertically or horizontally; in this case choose the horizontal option. With other heaters there is no option – in which case, ensure you attach it correctly, either horizontally or vertically according to instructions.

Your heater casing needs to warm up to the current temperature of the tank water. This will avoid the potential for cracking due to sudden temperature change upon activating the heater. We advise that you allow a minimum of 30 minutes before switching on your aquarium heater. 

After 30 minutes or so, switch your aquarium heater on and set to the temperature needed for your fish stock.

Wait until the water has reached the set temperature. We suggest giving a full 24 hours to ensure your tank water has reached the required temperature and remained there. Check your thermometer or external control panel as appropriate.

To ensure that everything is working properly, keep a close eye on the stability of the temperature for another 24 hours. At 6-hourly intervals, check the thermometer for another complete day to ensure there is no fluctuation in temperature. 

Once you’re fully satisfied that your new aquarium heater is in good working order, then you’re free to gently add your fish. It is worth the effort of ensuring the heater maintains a consistent temperature. Fluctuating temperatures in an aquarium causes stress and harm to your fish stock. 

How to Minimize Fish Tank Heater Power Usage

The cost of heating your aquarium can be an important financial consideration, particularly if you’re the owner of a large aquarium.

The ambient temperature in the room where your aquarium is housed, will affect the cost of heating the water in your tank. This may seem obvious, but can be overlooked when planning the placement of your aquarium. 

The colder the ambient room temperature, the more costly it will be for you to heat your aquarium water to the optimal temperature for your fish stock. And, of course, to keep it at a consistent level.

Do take time to carefully assess the optimum temperature for your fish. Adding any unnecessary degrees will have a direct impact on the power consumed by your aquarium heater. 

For example, it would use approximately 110 kilowatts to heat a 30 gallon aquarium to a temperature of 72 degrees Fahrenheit. However, it would use approximately 440 kilowatts if you increase the temperature by 10 degrees to 82 degrees Fahrenheit. So it’s easy to see where the money goes!

So take time to locate your tank in a room with adequate ambient temperature, and away from doors and draughts. Consider carefully the temperature you need your water to be – extra unnecessary degrees cost money!

Where to Place an Aquarium Heater

It’s important to place your aquarium heater in a suitable spot within the tank. This will ensure the heated water is dispersed uniformly and expediently. Avoiding discrepancies in temperature within the tank creates a more favorable environment for your fish. 

So in order to avoid hotter and colder patches within your tank, try and locate your aquarium heater close to where the flow of water is the greatest; for example the filter outlet of your aquarium pump. 

In an aquarium environment, the main method by which heat is distributed is via circulation. Therefore placing your heater close to your filter outlet makes perfect sense. It will at least help to prevent the formation of ‘hotspots’ around the heater with colder zones appearing at the regions furthest from the heater. If you have a reef tank with a sump tank, installing the heater here alongside the protein skimmer can work very well.

For more experienced aquarists who specialize in keeping delicate and sensitive fish stock, such as Betta fish, you may need to purchase additional kit. Wave makers and power heads which generate current can be employed to effectively fix the problem of uneven distribution of the heated water within the tank. This will help you avoid dead spots of stagnant water accumulating in corners of the tank. These dead spots will negatively affect water chemistry and will impact your fishes’ health. 

Many experienced aquarists advocate placing the heater low down in the tank; an inch or two above your aquarium substrate. A horizontal orientation is also recommended if possible; providing this is suitable for your type of heater. Obviously vertical heaters will need to be attached to the tank with the correct orientation, but keep close to the filter outlet of the pump. 

Many commentators talk about the fact that heat rises as a reason to locate your heater low in the tank. This is not quite true in the majority of tanks. For this process of convection to take place, the tank would have to be very deep. This is not the case with most home aquaria.

So in conclusion, our advice is to place your heater close to the pump. This will ensure a reliable and consistent distribution of heat within your aquarium. This even distribution occurs  via the straightforward process of circulation. 

One final note – ensure that no plants, decorations or other devices come into direct contact with the heater. Plants would certainly suffer if they were located too close to the direct heat source.

Conclusion 

So, don’t forget to carefully match your heater to the size of your aquarium. Don’t be tempted to purchase a heater that is too powerful. This can prove a costly decision, both in terms of initial outlay and ongoing running costs. And it will not provide any additional benefits for your fish. 

If you are the owner of a large aquarium, then do consider the option of purchasing two heaters; these can be installed at opposing ends of the aquarium.

Take your time installing and checking your new heater. Ensure that you’re happy with its capability to produce a consistent water temperature before introducing your fish to the aquarium.

There are many good aquarium heaters on the market currently. We have analyzed the pros and cons of these in our Top 10 Best Aquarium Heaters; we hope this has given you useful guidance.

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CoralRealm Staff

CoralRealm has been around for years. As one of the world's leading online Marine Biology publishers, you're in good hands with our team of experts. For more information, see our CoralRealm list of experts here.

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