
By Fishbowl Adviser
Published: 09:03 am
One of the most common questions people ask themselves when setting up an aquarium is whether or not they need a heater. While fish can regulate their body temperature, the water still needs to be at a certain temperature that is suitable for the type of fish you have. An aquarium heater will do just that – regulate the water temperature so your fish has the best possible environment to live in. Let’s take a look at some of the best aquarium heaters on the market!
Product Name | Wattage | Rating | Price | |
---|---|---|---|---|
Freesea Aquarium Heater | 50 W | 4.3 | Check Price on Amazon | |
Eheim Jager Aquarium Thermostat Heater | 150 W | 4.5 | Check Price on Amazon | |
Orlushy Submersible Aquarium Heater | 300 W | 4.6 | Check Price on Amazon | |
Pulaco Small Aquarium Heater | 25 W | 4.4 | Check Price on Amazon | |
Mylivell Fish Tank Water Heater | 50 W | 4.5 | Check Price on Amazon | |
Marineland Precision Heater for Saltwater or Freshwater Aquariums | 75 W | 4.3 | Check Price on Amazon | |
Freesea Fish Tank Submersible Heater | 50 W | 4.3 | Check Price on Amazon | |
Ratings are from Amazon at the time of publication and can change |
The Best Aquarium Heater
1. Freesea Aquarium Heater

- Temperature range between 63°F and 95°F
- Intelligent temperature control
- For submersible use
The FREESEA 25 Watt Aquarium Betta Fish Tank Heater with the submersible thermometer is a great addition to aquariums of 1 to 5 gallons. The aquarium heater is for submersible use only, which means the heater must be completely submerged while it’s operating and heating the tank. It can be installed on the inner side of the tank or the bottom.
It offers an adjustable temperature option between 63°F and 95°F. The temperature is easily adjusted with the diving thermometer that comes with the heater. And you can watch over the water temperature of the aquarium whenever you want. It also has intelligent temperature control to keep everything as it should be. The heater has an automatic constant temperature feature that stops the heater from heating the tank once it reaches a specific temperature. When the temperature is lower than what’s specified, the heater will automatically start heating.
2. Eheim Jager Aquarium Thermostat Heater

- For submersible use
- Thermo safety control
- On/Off indicator light
EHEIM Jager Aquarium Thermostat Heater 150W is a fully submersible heater that is made for fresh or marine water. It has laboratory-grade glass that is shatterproof and shock resistant and will protect the heater from any damage. The glass will also endure extreme temperature fluctuations. And it is free of any pollutants and is resistant to any biological or chemical substances.
The heater also has a thermo-safety control that protects against running dry and it will automatically turn off once the water level becomes too low. The heater will also power down once it’s removed from the water, and continue working once it’s placed back. And there is also an on/off light indicator that will make sure you know if the heater is functioning or not. As for the temperature adjustment, it has a readjustment ring that allows users to adjust the temperature precisely and recalibrate the heater and get a precise temperature reading.
3. Orlushy Submersible Aquarium Heater

- Automatic safety shut-off feature
- Fully submersible
- For universal use
The Orlushy Submersible Aquarium 300W Heater is the most suitable heater for marine reef tank setups. This fully submersible heater can be placed in aquariums of 50 to 80 gallons. The heater comes with an adjustable knob thermostat and 2 suction cups. It is made of 2mm thickened quartz glass that is suitable for both freshwater and saltwater aquariums. And it’s easy to hide in the tank, so it won’t bother your fish or interfere with an aquarium feeder if you want to install it.
The heater displays an area where you can adjust the temperature. It’s not completely accurate, but it’s easy to use – it can be turned easy and adjusted at small intervals. There is also a precise temperature dial that gives you complete control of the climate with just a 1-degree difference. There is also an automatic safety that will prevent overheating problems. Once the thermostat reaches the desired temperature, the heater will automatically turn off to avoid any overheating problems for both the fish and the heater. And with the power indicator light, you will always know when the heating is turned on or off.
4. Pulaco Small Aquarium Heater

- Automatic temperature control
- Easy installation
- Durable
The PULACO 25W Small Betta Aquarium Heater is a fully submersible heater that is ideal for small aquariums, which makes it suitable for betta fish tanks of 1 to 6 gallons. The heater has a quick and easy installation, and it can be placed vertically and horizontally. It’s easy to operate, allowing you to make your aquarium a suitable environment for your fish. Just make sure to not leave the product plugged in once the heater is out of the water. It’s also best if you install an aquarium water pump that will help circulate the water while it’s being heated.
The heater was built and designed with safety and durability in mind. There is automatic control of temperature feature that makes sure the water temperature is at 78° F without any adjustments needed. You just need to plug it in, turn it on, and wait for it to start working. It will heat up the tank, and once it reaches 78℉ it will shut down indicating that it’s off on the light indicator. And it comes with a free thermometer strip.
5. Mylivell Fish Tank Water Heater

- Automatic adjustment
- Universal use
- Fully submersible
The Mylivell Aquarium Submersible Auto Tank Heater is a fully submersible heater that comes with an adjustable temperature with a suction cup. The heater is made of high-quality quartz glass with double seal material and an advanced design that will ensure safe operation once it’s used. It is suitable for both saltwater and freshwater aquariums.
The heater can make sure that there is a constant warm environment for any tropical fish you have. The temperature of the heater is automatically adjusted with the temperature setting ranging from 65° F to 93° F with a display that is easy to read. It also has two suction cups that can be attached to the fish tank, along with the polarized plug that prevents electrical shock and allows easy aquarium maintenance.
6. Marineland Precision Heater for Saltwater or Freshwater Aquariums

- Automatic thermal switch
- Advanced mica core heating element
- Three window positions
The Marineland Precision Heater for Saltwater or Freshwater Aquariums with 75-Watt is a fully submersible heater for tanks of 20 gallons or less. The heater has an adjustable temperature dial that provides easy use when you need to set the temperature. The dial allows you to set the tank’s temperature by 1 degree with one click. There is also a thermal switch that automatically turns off when the temperature goes above the internally adjusted preset and turns it back on once it goes back down. The heater also has an advanced heating element with a mica core that is encircled by a mesh heating element that will provide superior heat transfer with great durability.
The heater integrates an adjustable temperature dial with an advanced heating element and a very visible temperature display that will provide precise control of the aquarium’s temperature and make sure your fish have an optimal temperature. The advanced mounting bracket makes sure that it is securely attached to the glass with 3 different window positions that provide a great view of the temperature display. The easy-to-view sliding scale will provide you with the requested temperature setting, while the top dial view will display the setting from another location.
7. Freesea Fish Tank Submersible Heater

- Automatic temperature control
- Multi-function LED temperature display
- Fully submersible
The FREESEA 50W Mini Aquarium Submersible Heater is an ideal heater for 10-gallon tanks that need to be fully submerged to provide the best heating of the aquarium. The heater’s multi-function LED temperature display will allow you to monitor the tank’s temperature at all times. The temperature is easily adjusted on the heater, but you can watch over the temperature of the water in the aquarium whenever you want. With the heater installed, you won’t need to get another thermometer.
The automatic constant temperature function will make sure that the heater stops working once the temperature reaches a specified value. When the temperature cools down and is below the set temperature, the heater will automatically start heating again. This way, you won’t have to worry about overheating. And it is also easy to use with great safety in mind. However, you need to make sure that the temperature control switch box is higher than the water’s surface and that the heater is fully submerged. For cleaning, make sure that the power supply is turned off at least 10 minutes before.
Best Aquarium Heaters Buying Guide & FAQ
After viewing the best aquarium heaters you can find on the market, it is important to have all the necessary information that will help your decision. It’s important that you know what to look for when choosing your aquarium heater and making your final decision.
What to Look For When Choosing Aquarium Heaters
What is the most important thing you know when choosing an aquarium heater? Well, it is essential to know what setup you have and what it can have in it. The choice of automatic fish feeder, pump, filter, and any other equipment can impact your decision. Apart from that, you need to know which type of heater you want, what is the right wattage your aquarium needs, and whether or not you need any additional features like automatic temperature control.
Different Types of Aquarium Heaters
When it comes to types of aquarium heaters, there are different types you can find. Apart from saltwater and freshwater heaters, you also need to know whether or not you need an immersible or submersible heater that is thermostatically controlled or preset.
Immersible aquarium heaters or hang-on heaters were once the only options you could find for your tank’s heating. Even though they are not the only option today, they are a popular choice because of their low cost. These heaters rely on a fairly constant high water level in the tank. If exposed to air too long, it can cause a malfunction of the heating element. If you’re on a tight budget, immersible heaters are a choice for you.
However, if you can afford it, you should get submersible heaters. They are a more reliable choice, and you have more options with this type. These heaters need to be submerged in water, but they won’t malfunction when exposed to water. They can be mounted to the back of the tank either vertically or horizontally. Most of the time, you will find those that are mounted horizontally, on a location near the substrate. And because they are intended for underwater use, they tend to be of a higher quality than you would have with immersible heaters, which makes them much safer to use – for both you and your beloved fish.
In terms of temperature control, you will find two types – thermostatically controlled and preset heaters. Most of the lower-priced preset heaters will heat the water to a temperature of 78° F, which is a good temperature for most fish species.
If you want to maintain the water temperature warmer or cooler, you will need to get a heater that will allow manual temperature setup, which is where thermostatically controlled come in. These heaters come with a thermostat that allows you to adjust the temperature you want to have. Along with that, most of these come with an automatic option that will make sure the heater is turned off once the desired temperature is reached or turned on if the temperature is below the desired value.
Choosing the Right Wattage
For choosing wattage, you need to make your decision based on the tank size. The unwritten rule of thumb is to have 5 Watts of heat for every gallon of water you have in the tank. It’s important to choose the right wattage as it will dictate the water temperature of your fish. Choosing a lower wattage for a big tank can cause uneven heating, while having a large wattage in a small tank can cause overheating problems, even with an automatic temperature control option.
Best Aquarium Heaters FAQ
When choosing the best aquarium heater for your tank you will probably have a lot of questions that need answers. To help you out with that, take a look at the list of frequently asked questions about aquarium heaters and their answers.
Q: Where should heater be placed in aquarium?
A: There is no written rule for the place you need to put the heater. Usually, it’s important to make sure you place the submersible heater below water levels and immersible heaters at water level. But, if you want advice on where is the best place to put the heater – the answer is at the greatest water flow. Placing the heater near the greatest water flow will contribute to better heating of the tank. The water will spread the heat evenly as it flows, making sure the entire tank has the same temperature.
If you have more than one heater in the tank, you will need to place them on different sides to make sure there is even heating of the water across the entire aquarium. Place the heaters across from one another on the sidewalls of the tank and avoid putting them in the center of the tank.
Q: What size heater do I need?
A: When picking the size of the heater, the general rule of thumb is to have 5 Watts of heat for every gallon of water, especially if you need to heat the water up to 10 degrees above room temperature or you just want to have a lid on your aquarium that will retain warmth and prevent evaporative cooling.
For a 20-gallon tank of this type, the suggested size of the heater 100 Watts. If your home is colder than the average (for example 65°F), you will need to raise the water temperature by 15 degrees of what the room temperature is, which means you should consider getting a heater of 150 watts.
Q: Can fish get burned by heater?
A: Aquarium heaters are completely safe for the fish. They usually have a protector sleeve to make sure the fish are not burned by the heater. However, there is a possibility of the protector sleeve falling off or getting broken, which can harm your fish. Even though it is rare, the heater can burn your fish without the protector sleeve.
Q: Do I need two heaters?
A: It’s not necessary to have more than one heater in the tank. However, if you have a very large aquarium, having two or more heaters can contribute to the comfort of your fish. Installing multiple heaters in large tanks will help you make sure your fish have the needed temperature. For example, with a 300-gallon tank, you will need 300 to 500 watts of heating that can be achieved with two 200 watts heaters that can be placed on each side of the tank.