It is important that you get the best 300 Watt aquarium heater because this device helps regulate the temperature in your fish tank. A well-regulated temperature means a healthy living condition for your fish.

A heater of this size is suitable for 75- to 100- gallon aquariums. This article will guide you on which 300 Watt aquarium heater is the best match for your tank. You can trust our judgment because we have tested multiple heaters and have gone through many online reviews to make our recommendations.

Let’s get started!

Comparison Chart

Products Suitable for Power cord length Suction cups Heater length

50- to 80-gallon saltwater and freshwater tanks 6 feet 2 11 inches

80- to 95-gallon saltwater and freshwater tanks 7 feet 2 13 inches

50- to 70-gallon freshwater tanks 4.9 feet 2 9 inches

80-gallon saltwater and freshwater tanks 6 feet 2 14.8 inches

What Are the Best 300 Watt Aquarium Heaters

1. Orlushy Aquarium Heater


  • Suitable for 50- to 80-gallon fish tanks.
  • You can conveniently adjust the temperature of the tank.
  • Fully explosion-proof.
  • The temperature dial works from 68 F to 89 F.
  • You can make adjustments in one-degree increments.
  • Automatically shuts off upon reaching the desired temperature.


  • It usually works four degrees off the preset temperature.


This is the best 300 Watt aquarium heater that you will find on the market. It comes with an adjustment knob that allows you to easily change the temperature according to the requirements. The best part is that you can use it inside a freshwater tank or a saltwater tank without any problems. This aquarium heater is suitable for tanks that are up to 50 to 80 gallons in size.

However, you will have to keep it closer to your power outlet because it only comes with a six-foot cable. Also, make sure the outlet is rated 110V to 120V.

The submersible aquarium heater displays an area to adjust the temperature. It is not going to be precisely accurate, but you can easily adjust in smaller increments. Moreover, this product is entirely explosion-proof thanks to the 2mm thick quartz galls that Orlushy has used to construct it.

There is an accurate temperature dial on it that allows you to conveniently alter your tank’s temperature within the range of 68 F and 89 F. One of the best features of this reliable aquarium heater is maintaining the temperature for a long while, so you won’t have to adjust it.


This 300w aquarium heater doesn’t require a lot of time to install and comes with a couple of suction cups that allow you to fix it inside the tank. The suction cups don’t lose their grip either. The heater can maintain the temperature of your tank for an extended period.

2. AQQA Aquarium Heater


  • It features an LED display for convenient viewing.
  • Ideally suitable for salt and freshwater tanks.
  • Works well with 80 to 95-gallon tanks.
  • Explosion-proof quartz glass.
  • Comes with temperature ranges of 59F to 93F.
  • Adjustments in one-degree increments.


  • Slightly heavy and loses its suction over time.


It is one of the best 300 Watt tank heaters and is made of quartz glass which is entirely explosion-proof and will keep your tanks safe while handling the water pressure.

It also features nickel-chromium coated with silicon carbide to ensure proper heat conduction for best results without taking too much time. The shell in which it is covered is made of PC material that is highly durable as well.

However, with so many quality materials used in the construction, the heater does get a little heavier. It tends to lose its grip on the aquarium wall from time to time. You can use another suction cup to keep it fixed in its place.

This 300W fish tank heater has a temperature range of 59 F to 93 F. Also, it has an automatic heating capability for one degree every couple of hours. It will automatically shut off when the desired temperature is reached. You can also change the units of temperature in the display to Celsius or Fahrenheit. Just press and hold the button to update the settings. However, you have to keep the controller away from water because it is not waterproof.

The device displays the current water temperature and the preset temperature. When the red light is on, it means that the heater is heating. The blue light indicates that the preset temperature has been reached and is constant. However, a flashing blue light means that the heater is not fully submerged.


This aquarium heater is built like a tank; therefore, it is ideal for larger aquariums. You can use it with your freshwater and saltwater tanks, and it is pretty easy to install. Just make sure that you go with an additional suction cup so your heater can stay in place and keep the controller out of water.

3. Freesea Aquarium Heater


  • Works well with 50- to 75-gallon water tank.
  • Suitable for 110V to 120V power outlets.
  • The temperature range is 63 F to 95 F.
  • Comes with a 12-month warranty.
  • The controller is waterproof as well.


  • It doesn’t feature explosion-proof quartz glass construction, so don’t submerge it too deep in your tank.


This aquarium heater is a top choice for heating your aquarium that is a bit small in size, close to 50 Gallons. It is not for larger tanks, and you also have to make sure that you don’t submerge it too deep into your tank because it doesn’t feature explosion-free quartz glass construction.

The digital aquarium heater does come with an adjustable temperature range from 63 F to 95 F. The temperature adjustment control itself is straightforward. Moreover, your purchase comes with a diving thermometer that will keep the temperature of your tank displayed at all times.

The 75 gallon fish tank heater also bobcats an automatic constant heating function. It means that when the water in your tank reaches a specific temperature, it will automatically shut off. This helps prevent overheating. However, you have to plug it into a closed outlet because it doesn’t come with a very long power cord.

Additionally, the aquarium heater comes with a one-year warranty. If you encounter any problem within the given period, the company will replace it for you.


The Freesea aquarium water heater is suitable for fish tanks that are around 50 gallons in capacity. It is not made of quartz glass, so it is not going to withstand much water pressure. Therefore, make sure you keep it close to the surface.

4. ViaAqua Aquarium Heater


  • Made of high-quality quartz glass.
  • Entirely submersible.
  • The temperature settings are quite visible.
  • Suitable to be used in freshwater and saltwater tanks.
  • Best for 80-gallon tanks.


  • It is a bit off on the temperature reading but stays consistent when it comes to heating the aquarium.


The ViaAqua submersible aquarium heater is a good option for both freshwater tanks and saltwater tanks. This heater is made of high-quality quartz glass, so it can take high water pressure very well. It means you can conveniently submerge it deep into your tank for the best readings.

Its design allows it to be utterly submersible while still displaying the current temperature. Temperature adjustment is quite simple with easily accessible control. Plus, it comes with double insulation waterproofing to ensure water doesn’t enter into its system.

It will also disperse heat evenly thanks to its ceramic heart core. The suction cups that this aquarium heater comes with are pretty strong. You won’t have to make any adjustments to these cups to keep them in place inside your aquarium.

Installation and use of this heater are pretty simple, and you don’t need to do much to get it to work. It does come with a long power cord but could have been longer. You might have to use an extension cable to make it work if your outlet is far away from our aquarium.


This is a top-quality 300-Watt aquarium heater that you can use either in saltwater tanks or in freshwater tanks. It is easy to install, but make sure you have your power outlet close to make it work even more conveniently.

Do You Really Need an Aquarium Heater?

Regular types of fish don’t really require an aquarium heater. However, you will need it when you are growing some specific types of fish like tropical fish. These species require a subtropical shift in their environment.

Fortunately, they can adapt well even in a 5-10 degree drop but you have to carefully provide them with an ambient environment. To simulate their natural living condition without using a heater, some hobbyists regulate the temperature of the room where their tank is. Doing this will keep the water inside the tank warmer. Some also use a variety of lights to bring the temperature up a bit.

However, this method doesn’t always work for everyone. It depends on how you can consistently keep your room temperature warm and the temperature endurance of the fish in your tank. So you might still end up buying a heater.

When Does Buying an Aquarium Heater Becomes a Must?

You will need an aquarium heater for sure if you live in a cold climate and your region sees a lot of extreme cold and snow. If the water inside the tank doesn’t get enough heat, your fish will end up dying.

Meanwhile, some fish species need a certain temperature level to reach a gender split ratio in their offspring. Using a heater will boost their fish breeding period.

Energy Efficiency and Cost

An aquarium heater’s primary purpose is to control the fish tank’s temperature and keep it stable. Fortunately, these heaters will only turn on when the temperatures are below the set temperature fit for the tank and your fish.

With that said, an aquarium heater will consume a lot of energy so your overall energy costs will increase. To manage this, avoid making abrupt changes in temperature.

Things to Consider When Choosing a Heater

Tank Size

You have to consider the size of your tank before buying an aquarium heater. All manufacturers provide the details on the suitability of their aquarium heaters for different sizes of tanks.

You have to follow these guidelines and only go for the right aquarium heater size. For example, all 300-Watt aquarium heaters are compatible with 50- to 95-gallon fish tanks.

A Backup Heater

You need to go for an additional heater if you are looking to get the best heating results without consuming too much energy. In this scenario, you should choose two small heaters instead of one large unit. They will be placed on separate sections of your tank and will allow the water to heat up evenly.

This will also enable you to keep using one even if the other breaks down for some reason. Just make sure that they come with automatic shut-off features as well.

Submersible vs In-Line

For regular users, choosing between the two models doesn’t matter much, and it might depend more on a personal preference.

In-line models allow water to go over them continuously. Submersible models need arm water, and you have to place them depending upon how the water flows. You can put them in the middle, at the bottom, and on the sides vertically or horizontally. If you are going to remove tank clutter manually, go for the in-line type.

In-line models are your best choice for small fish tanks. The submersible model is quite large and will take a big space in your tank, so they’re more appropriate for larger tanks, especially if you’re planning to buy two.


The winner of this roundup of the best 300 Watt aquarium heater is the Orlushy Aquarium Heater. It has a submersible design and is suitable for both saltwater and freshwater tanks.

With its 11-inches cord, you can conveniently place it near warm water flow for the best results. It can maintain the temperature for a more extended period and comes with an automatic shut-off feature.


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