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The Best Large Aquarium Heater: 150 To 800 Watts Analog And Digital

Even temperature distribution is particularly important in a large aquarium. So let’s find the best large aquarium heater to achieve this in your tank!

By Andy Birks
Last updated on

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best large aquarium heater

Choosing the best large aquarium heater for tanks around 40 gallons and above is key to ensuring you can maintain an even temperature throughout.

We assessed several heaters suitable for larger aquariums from top brands and found the Eheim Jager Aquarium Thermostat Heater to be our overall choice for its range of sizes, affordability, and ability to maintain a stable temperature.

But we’ve also included plenty of other options. So whether you have a particularly large tank over 100 gallons, or you are looking for an affordable budget option, we have every possible scenario covered for any large aquarium!

So let’s get started…

  1. Best Overall: Eheim Jager Aquarium Thermostat Heater
  2. Best Budget Pick: Orlushy Submersible Aquarium Heater
  3. Best Premium Electronic: Cobalt Aquatics Neo-Therm Pro Heater
  4. Best For Easy Calibration: Fluval E Electronic Heater
  5. Best For Ease Of Use: Aqueon Preset Aquarium Heater
  6. Best For 75 Gallon Tanks And Under: Aqueon Pro Submersible Heater
  7. Best For Tanks Above 100 Gallons: Hygger Titanium Aquarium Heater

Best Large Aquarium Heater Picks Reviewed

When choosing the best large aquarium heater we assessed a range of options from top brands, and made sure to include affordable budget options through to premium digital heaters for very large tanks.

1. Eheim Jager Aquarium Thermostat Heater


  • Heater Type: Submersible, adjustable
  • Dimensions (inches): 125W = 12.2 (length) x 1.4 (diameter), 150W = 13.6 (l) x 1.4 (d), 200W = 16.0 (l) x 1.4 (d), 250W = 17.7 (l) x 1.4 (d), 300W = 20.0 (l) x 1.4 (d)
  • Wattage: 125W, 150W, 200W, 250W, 300W (smaller Wattages available)
  • Key Features: Temperature range of 65 to 93°F, built-in thermostat, heating indicator light, thermo safety cut-off to protect from running dry, recalibration dial for temperature adjustment, shock-resistant shatterproof glass
  • Best For: Overall

Eheim produces the Jager aquarium heater in many sizes, which for larger aquariums range from 125 to 300 Watts. So you can easily find the power you need whether you have a 40 gallon fish tank or a 100 gallon aquarium.

Jager models are slim, but bear in mind they are long when compared to other heaters. For example, the 150 Watt model suitable for around a 55 gallon aquarium is 13.6 inches long. Although this will still fit many 35 (l) x 19 (d) x 19 (h) inch 50 to 55 gallon tanks.

As well as an easy-to-read temperature control, it has a separate calibration dial. While some owners report calibration can be difficult, it does improve accuracy as you can set the calibration dial to the actual temperature in your tank and the heater will adjust accordingly.

And once the temperature is set, the Jager is great at keeping it consistent. This will help keep your large aquarium at an even temperature throughout, regardless of if your room gets colder in winter.

There is a safety cut-out if the water level in your tank gets too low. This is particularly useful in a large aquarium where you may be doing bigger water changes, as it means if you forget to switch off the heater it won’t crack or shatter when out of the water.

Some owners report the lack of an overheat sensor means you do need to keep a separate aquarium thermometer and check it regularly. But overall many praise this heater as reliable as well as being affordable.

2. Orlushy Submersible Aquarium Heater


  • Heater Type: Submersible, adjustable
  • Dimensions (inches): 100W = 9.5 (length), 150W = 9.5 (l), 200W = 11.0 (l), 300W = 11.0 (l), 500W = 13.0 (l)
  • Wattage: 100W, 150W, 200W, 300W, 500W
  • Key Features: Temperature range of 68 to 89°F, 2mm thickened shatterproof quartz glass, built-in thermostat, heating indicator light, separate digital thermometer included
  • Best For: Budget Pick

Our pick, if you are on a budget, is the Orlushy submersible heater. It comes in a range of sizes, from 100 to 300 Watts. In fact, at 13.0 inches long, the 300 Watt model is one of the more compact heaters we’ve seen for the wattage. Great if you have a shallower tank like a breeder.

Note that Orlushy recommends each model be used for a slightly smaller aquarium than most heaters. So for example, where we would recommend a 100 to 150 Watt heater for a 40 gallon aquarium, you’ll need to choose at least the 200 Watt Orlushy for this size of tank.

It has a clear, simple-to-use control knob on top of the heater. And Orlushy also provides a free digital thermometer. So you can easily adjust and maintain the temperature for a wide range of mid-size or larger fish, such as the Duboisi Cichlid.

Some owners report the Orlushy maintains a stable temperature best at about the middle of its 68 to 89°F range. If you run it close to 89°F it can struggle to reach that temperature. So if you own Oscars that like a higher temperature of around 79-86°F, it may not be the best choice.

But overall many owners give high praise to the Orlushy, not only for its affordability but also for its robustness due to the 2mm thickened shatterproof glass.

3. Cobalt Aquatics Neo Therm Pro Heater


  • Heater Type: Submersible, adjustable, digital/ electronic
  • Dimensions (inches): 100W = 9.75 (length) x 2.25 (width) x 1.25 (depth), 150W and 200W = 11.0 (l) x 2.25 (w) x 1.25 (d)
  • Wattage: 100W, 150W, 200W (smaller Wattages available)
  • Key Features: Temperature range of 68 to 94°F, built-in thermostat accurate to +/- 0.5°F, touch-button control, set temperature and tank temperature LEDs, automated shut-off to prevent overheating, shatterproof casing
  • Best For: Premium Electronic

The Cobalt Neo Therm Pro is a digital aquarium heater that’s accurate to within 0.5°F. It also maintains a very stable temperature. So once you set it with the easy-to-use touch control, you can be confident your fish’s environment will stay at the right temperature.

It also has an automated shut-off which kicks in if the temperature goes too high, giving you extra peace of mind that you won’t accidentally harm your fish. 

And not only does the Neo-Therm show the temperature you’ve set with the clear LEDs, it also shows the current temperature of the tank. This really helps you monitor your tank’s real-time temperature and adjust it if needed.

All the Neo-Therm models are very compact in design. The 150 and 200 Watt heaters, for example, being 11.0 (l) x 2.25 (w) x 1.25 (d) inches. This flat, sleek design will easily fit in your large aquarium and you can conceal it with plants or decor if you wish.

Overall, while this premium heater attracts a premium price, many owners report it’s an easy-to-use and reliable heater coupled with excellent customer support if you need to use the 3-year warranty.

4. Fluval E Electronic Heater


  • Heater Type: Submersible, adjustable, digital/ electronic
  • Dimensions (inches): 100W = 11.75 (length) x 2.0 (width) x 1.12 (depth), 200W = 14.0 (l) x 2.0 (w) x 1.12 (d), 300W = 14.0 (l) x 2.0 (w) x 1.12 (d)
  • Wattage: 100W, 200W, 300W
  • Key Features: Temperature range of 68 to 93°F, adjustable in 1°F increments, two digital temperature sensors, LCD screen with VueTech color alert system, fish bumper guard
  • Best For: Easy Calibration

Fluval’s E Series digital heaters come in a range of sizes, with the 100 to 300 Watt models suitable for 30 gallon tanks to 75 gallons and above. They are adjustable between 68 and 93°F so you can support a range of large aquarium fish, from angelfish to discus.

We found the toggle switch easy to use and you can adjust in 1°F increments, so you can be confident in the accuracy of the temperature you’ve set. Once it’s reached, the Fluval E maintains the temperature well. So you can ensure a consistent environment for your fish.

The E Series has a clear digital display showing the current temperature, along with VueTech color alert. When the temperature is correct the display shows green, but if it’s out by +/- 2°F it shows blue for too cool, or red for hot. So you can easily see any issues and adjust if needed.

Set up is really simple as you just set the temperature needed, there’s no extra calibration required. And the dual temperature sensors help with accuracy. There’s also a bumper guard running the length of the heater, so your fish are protected from the heating element.

Some users report issues with placement as you do need to position the heater near your filter outflow to correctly circulate the heated water. But overall many report this is an accurate and reliable heater able to maintain a consistent temperature in their tank.

5. Aqueon Preset Aquarium Heater


  • Heater Type: Submersible, preset
  • Dimensions (inches): 100W = 6.4 (length) , 150W = 8.0 (l), 200W = 9.1 (l)
  • Wattage: 100W, 150W, 200W
  • Key Features: Preset temperature of 78°F, built-in thermostat accurate to +/- 1°F, LED heating indicator, automated shutoff to prevent overheating if not fully submerged, shatterproof casing
  • Best For: Ease Of Use

The Aqueon Preset is a great option if you prefer a preset heater for your large aquarium. It comes pre-calibrated to run at 78°F, so plug it in and it’s ready to use without any adjustment. Ideal if you are a beginner or want an easy-to-use large aquarium heater.

The LED indicator comes on when it’s actively heating your water. So if you use it along with a separate in-tank thermometer you can easily identify any faults if the temperature is too low but the light isn’t coming on.

It has an automated shutoff that will stop your heater from running when it’s not fully submerged. So there’s no danger of it cracking or shattering if it accidentally gets exposed above the water line during maintenance or a water change.

Some owners report this heater can be a little under-powered, so it’s best to get the larger model depending on your tank. For example, we’d recommend at least the 150 Watt heater for a 40 gallon tank. But overall many praise the Aqueon Preset for its reliability and ease of use.

6. Aqueon Pro Submersible Heater


  • Heater Type: Submersible, adjustable
  • Dimensions (inches): 100W = 10.5 (length) x 1.5 (diameter), 150W = 12.75 (l) x 1.5 (d), 200W = 12.75 (l) x 1.5 (d), 300W = 15.0 (l) x 1.5 (d)
  • Wattage: 100W, 150W, 200W, 300W (smaller Wattage also available)
  • Key Features: Adjustable heat setting 68 to 88°F, electronic thermostat accurate to +/- 1°F, shatterproof casing, fully submersible, auto shut-off, LED heating indicator, limited lifetime warranty
  • Best For: 75 Gallon Tanks And Under

The Aqueon Pro series has a range of heaters from 50 Watts up to 300 Watts. Whilst you could use the 300 Watt version in a 90 gallon tank, we found it best for aquariums up to 75 gallons as it’s at the higher end of the Wattage needed for a tank this size.

It can be mounted either vertically or horizontally, so it’s very useful if you have a breeder tank that can typically be shorter in height.

The easy-to-use adjustable dial allows you to set the temperature anywhere between 68 and 88°F, so will support most fish species you may want to keep in your larger aquarium. And the electronic thermostat is accurate to +/- 1°F so you can be confident in the temperature set.

It has an LED indicator that illuminates red when the heater is actively heating your water, and an auto shut-off to prevent overheating. So you won’t have problems with accidentally heating your water to dangerous levels.

Whilst some owners report the Aqueon Pro having issues within around 6 months to a year, it does come with a lifetime warranty to resolve these. And the majority of customers praise this heater for its ability to maintain a steady and accurate temperature.

7. Hygger Titanium Aquarium Heater


  • Heater Type: Submersible, adjustable, digital/ electronic
  • Dimensions (inches): 500W = 8.6 (length) x 3.4 (width) x 1.0 (depth), 800W = 10.2 (l) x 3.4 (w) x 1.0 (d)
  • Wattage: 500W, 800W
  • Key Features: Temperature range of 70 to 94°F, accurate to +/- 1°F, LED digital display showing current or set water temperature, rapid heating, corrosion-resistant titanium casing, overheat protection, auto shut-off when out of water
  • Best For: Tanks Above 100 Gallons

If you own a large aquarium of 100 gallons or above and are looking for a premium electronic heater the Hygger Titanium is a fantastic option. It comes in a 500 or 800 Watt version so will suit fish tanks of 100 up to around 180 gallons.

This heater is made of corrosion-resistant titanium with a protective bumper guard, so your fish are safely kept away from the heating element. It also has overheat protection so the display will flash if above 93.5°F and the heater will switch off at 97°F to avoid killing your fish.

You can set it anywhere between 70 and 94°F, so as you can set a lower temperature it’s even great for fish that prefer around 72°F such as fancy goldfish

The display is large and easy to read, showing the current or set temperature. So it’s really easy to check that your tank stays in the right range. And the touch control sits on the cable outside the tank, so you can adjust it without getting your hands wet.

A small number of owners have reported accuracy issues with the heater being 1 or 2 degrees out, so it’s always best to keep an additional thermometer in your tank. But the vast majority praise the Hygger Titanium for its compact design and stable heating in a large tank.

Factors To Consider When Looking For The Best Large Aquarium Heater

Choosing the best large aquarium heater is key in ensuring consistent and even heat distribution throughout your tank. Let’s consider the main things to think about before you make your choice.

orange and white fancy goldfish

Do You Need An Aquarium Heater In Your Large Fish Tank?

If like many aquarists you choose to keep tropical fish in your large aquarium then you’ll need the right heater to raise the water from room temperature (around 72°F) to the 74 to 80°F preferred by most species.

Do research your fish carefully though, as the right temperature can vary for different fish. Also bear in mind installing a heater is not just about raising the water temperature, it’s just as much about keeping the temperature consistent.

Goldfish, for example, that do well in larger 40 gallon tanks or above, prefer water that is around room temperature. But it’s still advisable to use a heater as if the temperature drops at night or in winter, or rises in summer, changes can lead to stressed fish, disease, and fatalities [1].

Heat Distribution In A Large Aquarium

Larger fish tanks need more heat to raise their temperature than smaller nano aquariums because the larger volume of water has a higher thermal capacity. So while it takes more heat to raise the temperature, it also loses heat more slowly [2].

But the heat produced by your heater needs to be evenly distributed through your tank to provide the right environment for your fish. This in part happens through natural convection, where the heated water rises and cooler water sinks, creating a current.

However, one of the main ways heated water is distributed through your large aquarium is through circulation and flow provided by your filter. So it’s important where your position your heater in relation to your filter.

Where To Place Your Heater

When positioning your heater you’ll need it near your filter where the water flow is high. By setting up your heater next to your filter’s outflow, the current will circulate the heated water to the cooler parts of your tank.

You can check that you are getting even heat distribution throughout your tank by keeping your thermometer at the opposite end to your heater. Your thermometer should give the same reading as the temperature set on your heater.

Installing The Best Large Aquarium Heater For Your Tank

When it comes to heating your large aquarium, many aquarists recommend you use two heaters equivalent to the total wattage needed rather than one. So instead of using a 300 Watt heater in a 75 gallon aquarium, you would use two 150 Watt heaters.

If you have two submersible heaters, for example, by placing them at either end of your tank you get better circulation of the heated water. It also acts as a failsafe if one heater malfunctions as you still have the other as backup.

Best Large Aquarium Heater Types

As with other fish tank sizes, submersible heaters are one of the most effective types for your large aquarium. But let’s look at the various different heater types you may come across.

Submersible Aquarium Heaters

A key advantage of submersible heaters when it comes to large aquariums is their efficiency. As they sit fully submerged below the water line they are particularly effective at directly raising the water temperature. Most are suitable for freshwater and saltwater tanks too.

They usually come with a built-in thermostat and are very good at keeping a larger volume of water at a consistently stable temperature. 

Many submersible heaters tend to be designed as plastic or glass tubes with a heated coil inside. But you can also get excellent digital submersible heaters for larger aquariums, often for tanks right up to 200 gallons, made of metals such as titanium.

In-Line Aquarium Heaters

These heaters sit outside your aquarium and are positioned on the outflow line from either a sump or filter system, such as a canister filter. They can be very effective for large aquariums as the circulation from the filter output ensures even heating of the water.

However, they can be quite complex to set up and can be prone to leaks if not installed correctly. They are also one of the most expensive types and so tend to be used by more experienced aquarists.

In-Filter Aquarium Heater

Occasionally some filter units, such as canisters, will come with heaters built-in. However, these are quite rare so we only mention them here for completeness.

We much prefer stand-alone heaters, like submersibles, where you can ensure you have the correct wattage for your tank size and also have the option of installing more than one heater for even heat distribution if you prefer.

Immersible Heaters

We’ve included immersible heaters here for completeness, although we wouldn’t recommend them for a large aquarium. In fact, they are actually quite uncommon and often tend to be found in smaller aquarium kits.

Immersible heaters hang from the back of your aquarium with a heating element that sits down below the water line. Because they are not fully submerged and the heating element tends to be smaller, they are often inefficient compared with submersible heaters, especially in large tanks.

Substrate Heaters

Again, we’ve included these for completeness as substrate heaters are much less common nowadays. They consist of a heating wire that is fixed to your tank under the substrate and so has to be installed before adding your gravel.

Substrate heaters can be good for smaller and mid-size planted tanks, but they won’t heat the water of a large aquarium. They are designed to create water circulation in your substrate to help promote the growth of aquatic plants.

How To Choose The Best Large Aquarium Heater

You’ll need to think about several factors when choosing the best large aquarium heater for your tank, such as power and safety. But let’s look at each of them, in turn, to help you decide.

discus in a large aquarium

Size Of Heater For Your Large Aquarium

As a larger aquarium contains more water than a smaller tank, it may seem obvious that your heater will need more power. But the size of heater your need is also based on your room temperature, and the temperature you need to maintain your water.

This means that manufacturers’ power recommendations for a particular heater, given in Watts,  are usually in the form of a range. This is broadly based on the principle that it takes around 2.5 to 5 Watts to heat one gallon of water [3].

But this is a rough guide, and if you live in a cold climate or need a higher temperature for a particular species it’s best to get a higher Wattage. As long as you choose a heater with a thermostat it won’t go over the temperature you set.

Wattage vs. Tank Size

The table below shows the power needed to maintain a temperature range of 74 to 80°F based on a room temperature of around 72°F [4]. Remember this is a guide though, so if you need the temperature higher or your climate is colder to go for a larger Wattage than shown.

Large Aquarium VolumeTo Maintain Approx. 75 to 80°F
40 US Gallons100 – 150 Watts
55 US Gallons150 – 200 Watts
65 US Gallons200 – 300 Watts
75 US Gallons250 – 375 Watts
90 – 100 US Gallons275 – 450 Watts
150 US Gallons450 – 750 Watts

In most cases, it’s advisable to go for the higher end of the ranges shown. Even with a higher Wattage of heater, as long as your thermometer has a built-in thermostat it won’t overheat your tank.

Temperature Range And Adjustability

When it comes to heaters for large aquariums some are preset, but most are adjustable for larger tanks. Preset heaters have the advantage that they’ll maintain a constant temperature, usually around 78°F, without the need for calibration.

But in most cases, an adjustable heater is the better option. These heaters usually have an adjustable range from about 65 to 95°F. So if you keep oscar fish in your large aquarium, for example, you can adjust the temperature to somewhere in their preferred range of 79-86° F.

When looking for an adjustable heater, opt for easy-to-use controls. Many submersible heaters will have an easy access control knob at the top. So do make sure it’s easy to rotate and set. Some heaters have their controls outside the tank on the cable, making adjustment even easier.

Temperature Readability And Thermometer

Many of today’s large aquarium heaters have digital LED displays making setting and reading the temperature simple. The best analog heaters will also have a clear dial, usually showing individual degrees so you can see what temperature has been set.

Remember that even the best large aquarium heater can often be a degree or so out. You can reduce any inaccuracy by calibrating your heater as per the instructions, although not all can be calibrated.

Whatever type of heater you have, you should still keep an aquarium thermometer in your tank positioned at the opposite end to your heater so you can keep an accurate eye on the temperature.

Safety Features

Submersible heaters that are fully submerged underwater tend to be the safest type of large aquarium heater. Because they are located below the water line there is less chance of positioning them incorrectly.

An indicator light to show when your heater is actively heating the water, rather than in standby, is a good feature to look for as it will help you identify if your heater is faulty if it’s not coming on when the water is cool. 

Another key safety feature is an auto shut-off. This switches off your heater if the water level is too low, preventing shattering of the tube. Some heaters also have an automated shut-off if the temperature in your tank gets too high.

Price And Durability

When it comes to finding the best large aquarium heater at the right price it can vary depending on the size and Wattage you need. 

Some budget heaters for large aquariums can be as low as around $20, whereas powerful digital titanium models can go right up to around $90. Also, remember if you plan to install two heaters in your large aquarium you’ll need to budget for that.

When looking for a durable heater, you can get several metal units that will last many years. But traditional plastic or glass rod heaters can be very durable too. Just make sure the material is shatterproof, and check reviews on Amazon and other sites to get other owners’ experiences.

Our Verdict

Large aquariums need an appropriate heater with enough power to raise the temperature so that the heated water can be evenly distributed throughout your tank.

The Eheim Jager Aquarium Thermostat Heater is an excellent and affordable choice for many large aquariums given the wide range of sizes available and stable operation. Or if you have a very large tank the Hygger Titanium is a fantastic premium heater too.

Whichever you choose from the list above there’s a heater to cover most scenarios here, so you’ll be able to find the best large aquarium heater for your tank!


We’ve answered some of the most frequently asked questions when it comes to choosing the best large aquarium heater. Take a look at the answers below.

Do I Need Two Heaters In My Large Aquarium?

Whilst not essential, many aquarists agree having two heaters in a large aquarium, particularly over 55 gallons, can help with heat distribution. It also means one can act as a failsafe.

How Do I Set Up My Large Aquarium Heater?

This can vary by type. Generally, the main thing is to let your heater establish the correct temperature for around a day, and check with a separate thermometer before adding your fish.

Where Should I Place My Heater?

Your heater should be placed near your filter’s outflow to ensure the most effective circulation of the heated water. If you install two heaters, place them at opposite ends of your tank.

How Often Should I Check My Heater?

Always keep a separate thermometer in your tank. Give the temperature a quick check daily, so if there are any issues with your heater you can pick up on them straight away.

Photo of author
Andy Birks
Andy is the owner of Simply Aquarium and manages the team of experienced writers on the site. He loves helping fellow aquarists and introducing new people to the hobby!

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