The Best Fish Tank Water Heaters Reviewed | iPetCompanion

The Best Fish Tank Water Heaters Reviewed

Buying the right equipment will go a long way towards maintaining a healthy aquarium, and choosing is the best fish tank heater is among the most critical pieces of equipment needed to keep your fish healthy. The best heater is easy to install and even easier to read. It should also come with a number of safety features to ensure you or your fish don't end up getting hurt in the process.

Here are some of the best options to consider:

Aqueon Pro Heater

BEST in Durability

  • Thermoplastic construcction
  • Fully immersible

Rated by: Amber

Fluval E Electronic Heater


  • High Quality & Durable
  • Alert system for temperature changes
  • Integrated guard for safety

Rated by: Amber

Tetra HT Submersible Aquarium Water Heater

Best for Ease of Use

  • Easy to use
  • Indicator lights
  • No adjustment needed

Rated by: Amber

The Best Fish Tank Heater: Our Top Picks

1. Aqueon Pro Heater

Quick Summary

Rated by: Amber

It is yet another high-rated submersible heater available today. It delivers great performance and looks quite sturdy because of its thermoplastic construction, which makes it shatterproof. Due to its construction, it is capable of dispersing heat quite effectively, without raising any concern about burning your fish.

Once it is in your tank, it is still easy to access it using the large control knob you can find on its top end.  Reading the temperature monitor is easy because of a clear monitoring light – the red light is for heating, whereas the green light tells you about the current temperature of the aquarium.

Another good feature is that it comes with an electrical thermostat, so you don't have to worry about not having enough water in the tank because the heater will turn itself off in such a situation. It starts working again once you submerge it back into the water.

So, overall, it's a good product to consider but it's worth mentioning that some users are not that happy with the reading they find on the temperature dial. Therefore, investing in an entry-level thermometer is a great idea if you're going for this heater.


  • It is made from thermoplastic for durability
  • It is usable both horizontally and vertically
  • It turns itself off when out of water


  • The temperature dial could've been better

2. Fluval E Electronic Heater

Quick Summary

Rated by: Amber

If you're looking for one of the best submersible heaters with precise temperature settings, you should look no further than this offering from Fluval.  This electric heater is available in different wattage, so you can pick one as per the size of the tank you have.  The great thing is that you can increase the temperature by 0.5 degrees between the temperature range of 68F and 93F.

You will like its slim profile, which looks secure and sturdy at the same time. It is possible to adjust it with ease – you don’t even need to take it off the bracket.  Using the bracket, you can mount it using various angles.  It is easy to pick an angle that makes the front screen more visible.

You won't face any trouble in terms of performance because it relies on a microprocessor with dual sensors. The benefit is that you get to see real-time water temperature and know when to make the changes. You will receive alerts in case the temperature varies by 2F from your pre-set temperature.

Overall, this fully submersible water heater delivers a solid punch, but do keep in mind that it may be a bit more expensive than other similar models in the market.


  • It allows you to set precise temperatures
  • It has an alert system to warn you temperature changes
  • It comes equipped with an integrated guard for safety


  • It may be a bit on the expensive side

3. Tetra HT Submersible Aquarium Water Heater

Quick Summary

Rated by: Amber

It is an effective water heater for your aquarium, and it is popular because it keeps everything simple. You will like the indicator lights, which keep you from overusing the heater. You will know exactly when it's working and what it's not.  The indicator light stays red while heating and turns green one your desired temperature has been reached.

It is quite suitable for most tropical fish because its electronic thermostat is designed to maintain a temperature range of up to 78F. You are also going to like how simple it is to install the heater. As it is fully submersible, it delivers great performance, but keep in mind that it is mainly suitable for tanks between 2 and 10 gallons of water.

Overall, the heater works great for proper temperature control, but it's worth mentioning that some users have complained about it overheating quite quickly. 

That's not something to worry about though, but it's still a good idea to use a thermometer to achieve the right temperature setting and avoid overheating.


  • It comes equipped with indicator light for easy use
  • It requires no adjustment because of its electronic thermostat
  • It can be installed horizontally or vertically


  • There may be chances of overheating

FAQ - A Buyer's Guide

Where Should a Fish Tank Heater be Placed?

You have to consider a number of things to decide where you can place your fish tank heater. For instance, the size matters a lot, which ultimately depends on the size of the tank. Ideally, you should choose a heater considering how many gallons in your tank. For each gallon of water, there should be a heater of up to 5 watts. It means you should have a 100-watt heater for a 20-gallon aquarium.

However, you should go for two aquarium heaters if you have a tank larger than 40 gallons. In this case, you should place a heater at opposite ends of your tank. You can opt for two 100-watt heaters to maintain a degree of uniformity in water temperature. Having two aquarium heaters is also a good idea because one will keep working even if one stops functioning for any reason whatsoever.

To select the best place for your heater for aquarium, you should also consider heat circulation and water flow. For instance, it is a good idea to place your heater where you notice high water flow, but at the same time, you should ensure that it doesn't suck newly heated water into the bio-filter. It is important because failing to consider this point would overheat your beneficial bacteria.

In this situation, you can try another option, which is to place your heater for fish tank near the filter outflow. This way, the heater will send the warm water in the circulation current into normal water.  Similarly, you may want to place your heater horizontally above the gravel – it should be close to the filter discharge, but ensure that you're going for fully submersible aquarium heaters.

A good idea is to take an air stone and add it under the filter intake. This is to ensure that denser cool water goes to the bottom of the aquarium. Moreover, you should bear in mind that you will get good results when you opt for a fully submersible heater. It will provide you with more freedom of placement as compared to a partially submersible aquarium heater.

While it is easier to find a suitable place for your fully submersible aquarium heater, keep in mind that it requires more maintenance, which is why it is a good idea to replace it at least once a year for optimum performance. To avoid maintenance problems, you should put your money on a high-end submersible heater, as it is designed to last for many years.

Are Fish Tank Heaters Safe?

Yes, fish tank or aquarium heaters with temperature control features are generally quite safe to use. However, it is still important to take some precautionary measures to avoid dealing with an unexpected situation. You can now find a variety of heaters designed for different types of aquarium, and high-end aquarium heaters with lifetime warranty are usually quite safe to use.

Here are a few tips to continue using your heater safely while keeping your tropical fish happy.

  • Be very careful when cleaning the tank or changing the water. Ideally, you should unplug the heater half an hour before touching the water.
  • Always ensure a proper water level when running the heater. If the level gets too low, leaving the heater running would increase the risk of cracking the glass. It could be an extremely dangerous situation for you and the fish. The last thing you want is a blown up aquarium because of the improper use of the heater.
  • Always pay attention to cleaning the heater regularly.  Regular cleaning will help keep it free of salt creep, which is the white buildup of minerals present in the water. Getting rid of salt creep is hard, especially when you're dealing with calcium and other minerals.
  • Never overlook the instructions to install and use your fish tank heater. You're put you and your fish at risk by not following instructions while setting up the heater. You should also use the right drip loops because some aquarium heaters are quite susceptible to burn out and salt creep.
  • Keep a thermometer handy all the time and check the water temperature regularly.  It is okay to use an entry-level thermometer, but sometimes, investing in a high quality one with automatic alerts and other interesting features is the best thing to do.

Maintaining the right water temperature is important and that makes your aquarium heater a critical piece of equipment. Therefore, you should never try to cut corners here and opt for the best quality heater with top-notch heating element to continue enjoying a great performance. Moreover, you should stay away from trying DIY heater repair, as it is sometimes better to discard the old one and switch to a newer model for a safer performance.

What Size Heater Do I Need for My Fish Tank?

In order to select the right sized heater, you should consider the water volume of the fish tank first. Similarly, considering the desired temperature and the average room temperature is equally important.

In most cases, the heater wattage should at least be 2.5 watts per gallon of total water volume in the fish tank. Sometimes, larger heaters are required for very large aquariums, and sometimes, it also depends on what water temperature you want to achieve.  You can use multiple heaters to achieve the required temperature.

The temperature in the room where you want to place the aquarium needs to be considered always. For better adjustment, you should find the average room temperature and then subtract the number from the target temperature you want to have in the aquarium water.

How can I Heat my Betta Fish without a Heater?

Though investing in a heater is probably the best way to heat your fish, you can surely find some alternatives to try when your heaters fail and you're looking for a replacement.  Here are some options to consider:

  • You can make use of a thick towel or blanket. Simply wrap it around the aquarium to create a layer of insulation and keep the water warm. For smaller tanks, a towel would serve well. You may need a larger blanket for larger fish tanks.
  • You should also consider changing the location of your fish tank. Moving it to a warmer area in your home is a great idea.  Similarly, you can also consider using your own heater to increase the room temperature. Raising the temperature in your room or house will also help raise the temperature in the fish tank, and sometimes, a minor increase in temperature is all that you need to keep your betta fish happy and protected.
  • You can also raise the water temperature in the tank by filling up a plastic bottle with boiling water and then emptying it to place inside the fish tank.  You can leave the bottle there for some time. Use the thermometer to ensure that you've achieved the optimum temperature. Just keep in mind that you should constantly monitor the temperature because keeping it between 78 and 82F is important. You may end up harming your betta fish if the temperature is too high or too low.

The Best Fish Tank Water Heater of All

Overall, you should make no compromises over quality when buying the best fish tank heater. Be sure to pay attention to the size of your aquarium as well as the number of fish you have. Also, put your money on a high-end heater to enjoy great performance without any safety issues. Fluval E Electric Heater is probably the best choice because it features the latest advancements in tech and safety, and is also quite easy to maintain. So, go ahead and make a purchase for a healthy aquarium!

About the Author Steven