5 Best Aquarium Heaters in 2022 – Buyer’s Guide

Oct 13, 2020

5 Best Aquarium Heaters

Fish, reptiles, and amphibians are ectotherms. It means they can’t regulate their body temperature on their own. Instead, they rely on external factors like sunlight or a heated rock surface to maintain the desired body temperature. Now, our fish tanks aren’t exactly exposed to the sunbeams or feature magical self-heating rocks, and that’s why you need to buy them a heater. With the help of rigorous research and my own fish keeping experience, I’ve come up with a list of 5 best aquarium heaters for you.

5 Best Aquarium Heaters At A Glance

  • Aqueon Adjustable Pro Aquarium Heater
  • Fluval E Electronic Heater
  • Cobalt Aquatics Flat Neo-Therm Heater 
  • Hydor ETH In-Line External Aquarium Heater 
  • Tetra HT Submersible Heater 

My Top Choice 

My top pick is Fluval E Electronic Heater because it is packed with too many features packed in one product that is especially much needed for beginners. 

Whether it’s the heater guard to protect fish from heat shocks or flexibility to regulate temperature, I’m confident that this heater will have my back on several occasions. Must say, the 5-year warranty by Fluval is quite a nice gesture too. 

That being said, if you’re on a budget, go for Tetra Submersible heater. It’s packed with awesome beginner-friendly features for a very affordable price. 

And if you’re looking for an in-line heater that won’t mess with your tank’s appearance or space, while offering all the benefits of a submersible heater, Hydro ETH In-Line External Aquarium Heater is the way to go. 

Aqueon Adjustable Pro Aquarium Heater

Adjustable Heat Setting:Yes
Power Indicator Light:Yes
Warranty:Lifetime

This heater by Aqueon makes some impressive claims and deliver on them. Each heater is made with a shatterproof, plastic housing that lends them a strong built. 

The Pro Aquarium Heater features an electric thermostat that has an auto shut off feature. 

On top of that, it is equipped with advanced gravity technology. 

The heater will turn off automatically if the top of the heater falls lower the base of the heater. Thus, it’s safe to say that this heater offers decent safety measures. 

Similarly, like all other heaters from Aqueon, these to feature LED heat indicators. These indicators illuminate to signify when the heater is actively heating. 

In addition to the adjustable heat settings, adjustable suction cups are also present, which allow you to install the heater in a vertical or horizontal position easily. 

Available in four different capacities—50W, 150W, 200W, and 300W—the Pro Aquarium Heater is easily a top contender for best aquarium heater. 

Pros:

  • Adjustable heat setting that allows regulation between (68 to 88°F)
  • Advanced gravity technology ensures the safety
  • Shatterproof and completely submersible 
  • Lifetime warranty 

Cons:

  • The customer service received mixed reviews 

Fluval E Electronic Heater 

Adjustable Heat Setting:Yes 
Power Indicator Light:Yes
Warranty:5 years

Fluval E Electronic Heater is one of the most popular heaters among aquarists. 

The fully submersible heater comes in four capacities: 100W, 200W, and 300W—which gives you greater flexibility to choose from.

For example, a 300W heater can regulate up to 100 gallons of water within a temperature of variation of 68° to 93° F. You can also change the temperature setting between Celsius and Fahrenheit. 

Likewise, these heaters have a dual temperature sensor that displays the real-time and required water temperature. This feature is incredibly handy for beginner fish keepers.

Fluval hasn’t cut any corners with heater—especially when it comes to your fish’ safety. The heater comes with an in-built fish guard that will protect your fish from coming into contact with the heater. 

Also, the LED light indicator alters its colour when the water temperature has changed past the preset level.

Pros:

  • Features many safety features suitable for a beginner 
  • Sophisticated, lean design 
  • Adjustable height 
  • In-built fish guard ensures fish’s safety

Cons:

  • Installing it horizontally might void the warranty 
  • The temperature may alter by up to 3 degrees

Cobalt Aquatics Flat Neo-Therm Heater 

Adjustable Heat Setting:Yes 
Power Indicator Light:Yes
Warranty:3 years

For its price range, it wouldn’t be wrong to say Cobalt Aquatics Flat Neo-Therm is the best aquarium heater as it doesn’t only function well but also look good.

The heater sports a flat, sleek design unlike any other heater in the market. Moreover, the reversible bracket allows this fully submersible heater to be placed in different positions within the tank. 

In terms of capacity, Cobalt Aquatics offers a wide variety. You can choose from six different options: 25W, 50W, 75W, 100W, 200W and 300W. It basically covers all aquarium sizes. 

As for temperature, you can easily regulate it anywhere from 66°F – 96°F with just a simple touch. The precision is also quite commendable as the heater is accurate to within 0.5 of the set temperatures.

The LED screen displays both current and set temperature, while the automatic shutoff function and thermal protection circuitry reduces the risks of hazards significantly. 

Similarly, a resin exterior means you don’t have to worry about it shattering. 

Pros:

  • Shatterproof resin casing ensures the safety 
  • One-touch temperature setting 
  • Flat, modern design 
  • Auto-shutdown feature to avoid overheating 

Cons:

  • Suction pipe needs to be replaced soon as they might stop sticking after some time
  • Quite expensive 

Hydor ETH In-Line External Aquarium Heater 

Adjustable Heat Setting:Yes 
Power Indicator Light:No
Warranty:2 years

For those who don’t like the bulky look of having a heater inside the tank, it can just be the best aquarium heater out there. Let me tell you why. 

For starters, it is an external thermal heater that works great for both tropical and marine tanks. Also, if your tank doesn’t have much space for a heater, this will get the job without any compromise. 

The heater is fortified with a positive thermal coefficient (PTC) technology. Thus, the self-limiting PTC heating element ensures maximum safety against even slightest chance of overheating. 

It works by heating the water on its way back from canister filters or sump to the tank. 

For sizing, you can choose from three options: 200W 1/2”, 200W 5/8”, and 300W 5/8”.

While the heater itself is very simple to install and run, the high-precision electric temperature control offers better regulation as well. 

  • Adjustable Heat Setting: Yes 
  • Power Indicator Light: No
  • Warranty: 2 years

Pros:

  • PTC technology prevents risks of overheating 
  • Temperature swing of just 0.1 degrees 
  • Simple to set up and use 
  • Sit outside the tank and hides well

Cons:

  • Loud clicking sound when the heater turns on and off
  • Temperature dial moves easily 

Tetra HT Submersible Heater 

Adjustable Heat Setting:No
Power Indicator Light:Yes
Warranty:2 years

A non-adjustable heater that’s suitable for aquariums ranging in size from 2 to 10 gallons, the HT submersible heater by Tetra can be the best aquarium heater for first-timers.

You can choose from two options: 50W and 100W.

It performs quite well and offers great value at a very affordable price. This is among the cheapest yet reliable and well-functioning heaters available in the market. 

The heater comes with an LED light indicator that turns green when the temperature setting is right and red when it’s warming the water. Also, the heater will shut off automatically if it electrically shorts.

Although you can’t manually adjust the temperature, the electronic thermostat automatically sets the temperature to 78°F. It is just the right temperature for most tropical fish species. 

While the strong glass tube is shock and heat-resistant, the use of silicon carbide crystals in the casing ensures improved heat distribution and transfer. 

Pros:

  • Superb value for money 
  • Slim design, easy to conceal 
  • Green and red light indicators offer easy regulation
  • Shock and heat-resistant 

Cons:

  • Can’t customize the temperature 
  • Can be prone to overheating 

What’s The Ideal Water Temperature For Fish?

For a freshwater aquarium, the ideal temperature ranges between 75-80°F (24-27°C).

On the other hand, saltwater species thrive in temperature ranging anywhere between 75-78°F (23-25°F). 

New fishkeeping hobbyists are often susceptible to overlooking the importance of maintaining the ideal water temperature. We might think that a change of a degree or two won’t make much difference. 

However, even the slightest drop in temperature over a 24-48 hours period can have grave consequences on your fish’ health—ranging from weakened immunity to digestive complications. 

Thus, when it comes to buying an aquarium heater, there are a number of things you need to consider. 

What to Consider When Buying an Aquarium Heater?

What Kind Of Fish Do You Have?

The type of fish you are stocking is the number one factor to consider before buying a heater or any other equipment. Fish like bettas, angelfish, guppies, and tetras prefer warm and stable water all the time. Whereas, some species like Clown Killifish and Cherry Shrimp thrive the best in cold water. 

What’s The Size Of Your Tank?

Bigger the tank’s capacity, the more powerful the heater should be. For large tanks, aquarists often prefer to use two smaller heaters on the opposite end of the tank. That way, the heat is distributed more evenly, and the temperature is much more stable. 

The Location Of Your Heater

The location of the heater within your house also plays a determining role when choosing an appropriate heater. If the room or the tank receives enough sunlight throughout the day, the water will naturally be warm to an extent. You should consider things like whether it’s situated right beneath an air conditioner, or if it’s in a room that’s hot during the day and cold at night. 

What’s Your Budget?

Although we like it or not, the budget is the most influential factor when it comes to buying an aquarium heater. Premium brands don’t always translate to a better heater. Still, it’s always smart to invest in a known brand even though it means spending a couple of dollars extra as they usually have solid built and safety standards. 

The Five Most Common Types Of Heater

The leap in technology has made it very easy for us to maintain stable water temperature in our tanks. 

In fact, aquarium heaters have even gone as far as having fully-programmable electronic systems that maintain a tank’s eco-system. 

However, finding the best aquarium heater for you boils down to factors like tank’s size, species, and your budget. 

The five most common types of aquarium heaters are:

  • Immersible/hanging heater
  • Submersible heater
  • In-line heater
  • Substrate heater
  • In-sump heater
  • Filter heater

Immersible/Hanging Heater

Immersible heater hangs over the top of the tank at the back. But the heating element, which is encased in glass, is submerged in the water.

You’ll need to drill a hole in the hood to let the heater sit.

These types of heaters are quite common and cost-effective. That’s why they are often included in a beginner’s aquarium kit.

Drawback

While hanging heaters are ideal for freshwater tanks, it doesn’t work quite well in brackish or saltwater setups. 

Submersible Heater

Submersible heaters are built to fully sit under the water. 

That’s why you’ll have many options for its placement. But it’s better if you place it adjacent to the inlet of the filter, so it warms the water up as it flows back to the tank. 

Also, make sure that it doesn’t touch the substrate material, and fish have enough space to move around it. 

These heaters come with an LED light indicator that lets you when it’s on. 

Generally, these are more effective, and a tad bit pricier than immersible/hanging heaters.

Drawback

The glass encasing the coiled heating element is prone to cracking if the unit overheats excessively.

In-line Heater

An in-line heater’s design allows it to be hooked to the filtration system—most commonly between the filter and the tank. 

Hence, it will warm the water up on the way back to the aquarium. 

Since these heaters are made with heatproof plastic, the chance of a fire or electrocuting are nullified. 

Also, they’re particularly well-suited for big tanks, or if you have aggressive species, like some cichlids, that like to mess around with the equipment.

Drawback

Since it is positioned outside the tank, there are slight chances of leaks.

Substrate Heater

Substrate heaters are often used as an addition to support the primary heater. 

They come in the form of wires and heating coils that are fixed to the base of the aquarium before being covered with the substrate. 

Substrate heaters rose to fame in the 90s due to their usefulness in planted aquariums. Their heating facilitates gentle water movement, which in turn, stimulates plant growth. 

Drawback

Substrate heaters aren’t powerful enough for total-tank heating.

In-sump Heater

In-sump heaters are quite uncommon compared to other products in this list, but they pretty much offer the same benefits as an in-line heater. 

As the name suggests, in-sump heaters are positioned in the sump system to save pace. These heaters have an internal thermostat that will turn them on and off depending on the temperature you set it at.

Drawback

There’s a slight chance for heat loss from the water going into your aquarium.

Honorable Mention – Filter Heater

Some filters come with an in-built heater. Thus, when water passes through the heater, it heats up simultaneously. 

Where Should I Place My Heater?

As you learned in the above section, the placement of the heater depends entirely on your heater’s model. 

Don’t worry. Each heater model with come with a detailed manual on how to install and operate it. 

How Many Watts Will My Aquarium Heater Need?

The answer to this depends on the tank’s water volume, the average room temperature, and the required water temperature. 

For heater wattage, the most practiced guideline is to use 2.5-5 watts per gallon of water volume in an aquarium. 

Calculation: 

To adjust for the room’s temperature, subtract the average room temperature from the desired temperature for the tank water. 

Does My Aquarium Need Two Heaters?

If you have a big tank and your heater’s capacity doesn’t match up with the required water temperature, you might want to invest in another one. 

Here are a few benefits of adding a second heater:

  • In cold regions, it would be ideal to buy a second heater as it would take some pressure off the first one.

  • Having a backup is a safe and recommended option if one of the heaters stops functioning. 

  • Having multiple heaters also come handy when you have to acclimatize new species in a bucket for a while.

How Often Should I Check My Heater And Water Temperature?

Setting up a water heater is not a one-time job. You have to constantly check it for any problems and monitor the water temperature on a daily basis.

Of course, you’ll know when you smell something to burn or notice a small puddle near your tank. However, by then, it might be too late.

Conclusion: 5 Best Aquarium Heaters in 2022

Like I have already stated before, the choice of best aquarium heaters depends on the needs of your tank, and each tank is unique. 

What works for someone may not work for others, and it’s completely normal.

In fishkeeping, some compromise can be made when it comes to decorations and toys if you must. But when it comes to getting something as crucial as an aquarium heater, you can’t afford to cut corners. 

rohit gurung author at urbanfishkeeping

About Rohit Gurung

My never-ending love and fascination with Aquascaping started when I received a red-eared turtle for my 10th birthday.

Apart from researching and writing, I spend hours gazing at my 3 turtles. And yeah, I bask alongside them too.