5 Best Heaters for 20-Gallon Tanks – Versatile and Easy to Install!

A high-quality aquarium heater is essential for the health and wellbeing of your aquarium fish. We reviewed the best aquarium heaters for 20-gallon tanks and ranked them on our list of favorites.
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Last updatedLast updated: December 31, 2021
Picked By Fish is reader-supported. We may earn a commission through products purchased using links.
Picked By Fish is reader-supported. We may earn a commission through products purchased using links.

Catering to the health of your aquarium fish is integral in maintaining an ideal aquatic environment. So, how can you ensure your fish are living in a personal utopia? What can you do to ensure they can thrive in their environment? A good heater is the first step. There are a lot of options to choose from, and it can be tricky deciding which is the best heater for a 20-gallon tank. Ideally, it will be compatible with your specific tank in terms of size, design, and weight.

The amount of power transmitted and its temperature range are important too. Beyond that, you need to consider the cost of installation and any other adjustable settings the heater offers. In this guide, we reviewed the best heaters for a 20-gallon tank and ranked them from editor’s choice to best value and more. We’ve also included a helpful guide of everything you need to consider when choosing your aquarium heater.

Top 5 Heaters for 20-gallon Tanks Reviewed in 2022

1.

Orlushy Submersible Aquarium HeaterEditor’s Choice

Features
  • Power: 100W
  • Tank capacity: 10 to 20 gallons
  • Temperature range: from 68 to 89°F
  • Size: 10.79 x 3.58 x 2.24 inches

More features: suitable for marine saltwater and freshwater; adjust knob; 6-feet power cord

The Orlushy submersible aquarium heater comes in five different sizes ranging from 100W-500W. The glass composition is 2mm thick and is virtually shatterproof, so it can withstand the weight of water in your aquarium. It can be used in salt or freshwater tanks and can easily be hidden out of sight on the floor or attached to the aquarium wall. This aquarium heater allows you to adjust the temperature between 68-89-degrees F.

Unlike other 20-gallon tank heaters like it, the Orlushy heater includes an accurate digital thermometer to ensure your tank won’t overheat. It also has an updated design from previous models to allow the heater to fit discreetly into your tank, regardless of the tank size. This is a major improvement from the previous design as it was more difficult to make sure the heater was completely submerged in the tank before.

What makes it special?

  • This 20-gallon tank heater earned our spot for Editor’s Pick because of its updated design and ability to be easily hidden inside of the tank. We also like the inclusion of a digital thermometer to make measuring the water temperature much simpler. On top of that, it’s also very sturdy and heavy despite its small size. While that may seem like a downfall, a sturdier heater means it’s far less likely to crack from underwater pressure.

What cons did we find?

  • Although this heater has plenty of advantages, there are a few things we’d like to note. In some cases, customers have mentioned that the heater won’t heat to the exact temperature they need. In fact, there have been some reports of the temperature range falling closer to 15 degrees rather than the 21 degrees advertised. With that said, it’s still entirely possible to maintain a healthy water temperature for your fish with the temperature settings offered with this tank heater.
RELATED: 10 Best 10-Gallon Fish Tank Heaters – Perfect for Small Spaces
2.

FREESEA Aquarium Heater Fish TankPremium Pick

Features
  • Power: 100W
  • Tank capacity: 10~20 gallons
  • Temperature range: 59 to 94°F
  • Size: 2.5 x 1.5 x 3.5 inches

More features: LED display; automatic constant temperature function; 100% submersible use only

The FREESEA tank heater offers a temperature range of 59 degrees F to 94 degrees F and is designed for tanks from 10-20 gallons. It comes with an automatic temperature function that will turn the heater on and off when the tank gets too cold or too warm, respectively. The heater will only work when it’s fully submerged, but there’s an external temperature controller to make temperature adjustment much easier.

This aquarium heater is superior to other heaters like it for a variety of reasons. First of all, the heater’s real-time digital temperature display is built right into the heater, so you don’t have to worry about purchasing and installing a separate thermometer. On top of that, the temperature adjustment controller is attached to a part of the cord that isn’t submerged. This makes adjusting the tank’s water temperature much safer and less messy.

Why did it make our list?

  • This aquarium heater earns our spot for Premium Pick as it offers several unique benefits. We like this option specifically because of your ability to adjust the temperature without sticking your hand in the water. You don't have to worry about any potential for burning or shocking yourself, and you can easily see when your fish may be in water that's too hot or too cold. We also love this heater because it has sensors that automatically turn it on or off when needed.

What is not ideal about it?

  • With that said, there are a few things to keep in mind about this 20-gallon tank heater. If you own Betta fish, you may not want to go with this heater for your tank. There have been multiple reports from customers where their Betta fish got caught in the coils of the heater while swimming near it and died. The cord that comes with the heater is also shorter than others, so you need to make sure your tank is near an outlet for it to work.
Features
  • Power: 50W
  • Tank capacity: 5-20 gallon
  • Temperature range: 68 to 93°F
  • Size: 7.8 x 1 x 1 inches

More features: adjustable; submersible; 2 mm thickened explosion-proof

The Hitop aquarium heater is built with 2mm of thick shatterproof glass, making it more durable and shatter-resistant than others like it. The temperature settings on this heater allow you to choose from 68-93 degrees Fahrenheit and a thermometer sticker is included to help ensure your tank is at the correct temperature. The heater is suitable for salt or freshwater tanks and has an automatic turn-off setting when the tank reaches the set temperature.

Unlike other aquarium heaters, this one is unique in that it will automatically turn off when the set temperature is reached. It’s also superior to other models because it’s easy to discreetly hide within the aquatic landscape of your tank. Its construction of 8-shot multi-branched wire ceramic heating makes the dissipation of heat throughout the tank much more even. This is ideal for ensuring the tank is evenly heated.

What makes it special?

  • The Hitop 20-gallon tank heater made our choice for best value specifically because it comes with the same unique features others like it come with, but with a much friendlier price tag. Aside from its value, it also has a safeguard built in for accidental breakages. Instead of shattering and sending shrapnel throughout the tank, the heater is designed to make the glass safely flow to the bottom of the tank if the heater happens to break.

What cons did we find?

  • Although this heater has great value and it has a safe design, it’s also bulkier than other heaters. Because it’s bigger and bulkier, it’s more difficult to hide amongst the aquatic landscape and can become a bit of an eyesore. Some customers have also expressed concern over the difficulty in adjusting the temperature. This difficulty can be frustrating when trying to make sure your tank water is at the correct temperature for your fish.
4.

Uniclife Aquarium Heater 100 WattUser-Friendly Choice

Features
  • Power: 100W
  • Tank capacity: up to 20 gallons
  • Temperature range: 68-93°F
  • Size: 9.7 x 1 inches

More features: comes with a thermometer; can be used in both freshwater and saltwater

The Uniclife heater can be used in salt or freshwater tanks and can be used in tanks between 10-25 gallons. The glass exterior is 2mm thick and has a bottom clash-proof cover to further prevent any damage. The temperature is adjustable via a red knob at the top of the heater and has a range of 68-93 degrees Fahrenheit. The temperature control is visible, and the package comes with a thermometer sticker to help keep track of the tank temperature.

This heater is set apart from others as it’s built for prolonged use. It also has automatic shut-off sensors, and the knob for temperature adjustment is easier to use than other models. The stick-on thermometer that comes with the heater is also easier to read than other similar models.

What stands out?

  • We like this aquarium heater largely due to the fact that it’s incredibly easy for people to use. Although it doesn’t come with a digital temperature reader, the stick-on thermometer has a color-coded system that allows you to see the current temperature (blue) in comparison to the temperature you have set (red). On top of that, the red knob is easy to turn when you need to adjust the aquarium temperature, and there's a helpful indicator light that tells you when the heater is running.

What cons did we manage to find?

  • With all of this in mind, there are some who have expressed concern about the temperature settings of this heater. Although the knob makes temperature adjustment easier, it’s commonly reported that the actual temperature isn’t 100% accurate. Some have complained that their water is always either slightly too warm or slightly too cold for their fish, causing the fish to stress out. Some have also expressed concern over the quality of the suction cups that come with the heater.
5.

Mylivell Aquarium HeaterSpace-Saving Pick

Features
  • Power: 100W
  • Tank capacity: 20-45 gallon
  • Temperature range: 65-93°F
  • Size: 11.6 x 2.7 x 1.5 inches

More features: adjustable; fully submersible; both suiting for fresh or saltwater aquariums, safe

The Mylivell aquarium heater is made with shatterproof quartz glass, double seal material, and a guarantee for safe operation. It also comes with automatic temperature adjustment with an easy-to-read temperature display with a range of 65-93 degrees Fahrenheit. It can also effectively heat tanks up to 40 gallons. To ensure optimal safety, the plug is polarized to prevent electrical shocks to you and your fish.

Unlike other 20-gallon tank heaters, this one is easy to hide amongst your aquatic landscape. It also has a switch design for temperature adjustment to ensure accurate temperature settings. The heating component is also protected by a layer of glass, so you don’t need to worry about your fish getting curious and stuck between the coils.

What are our favorite features?

  • We chose this one to round off our favorites because of its discreet design. It’s more compact than other aquarium heaters, which is great for anyone who doesn’t want it in the way of a well-thought-out landscape. It’s also designed to safely shatter in the event of equipment issues. Rather than spewing shrapnel after glass popping, it remains intact until you can safely remove the heater from the water. This is great because you don’t need to worry about your fish sustaining any injuries.

What could be better?

  • With all of this in mind, we would like to note that the glass that encases the heater is thinner than other models. Because of this, you need to be extra careful when handling it to avoid shattering it before and during installation. Some customers have also expressed concern over the thermometer and heater not syncing up with each other. For example, one person stated that while they set the temperature to 83 degrees Fahrenheit, the thermometer read only 74 degrees Fahrenheit.

Things to Consider

Regardless of the 20-gallon tank heater you choose, there are different models that will work better for different tasks and situations. Because each tank is different, it’s important to consider all factors before clicking on “add to cart.”

What to look for in a heater for a 20-gallon tank?

When shopping around for an aquarium heater Trusted Source Water warming increases aggression in a tropical fish | Scientific Reports Our understanding of how projected climatic warming will influence the world’s biota remains largely speculative, owing to the many ways in which it can directly and indirectly affect individual phenotypes. Its impact is expected to be especially severe in the tropics, where organisms have evolved in more physically stable conditions relative to temperate ecosystems. Lake Tanganyika (eastern Africa) is one ecosystem experiencing rapid warming, yet our understanding of how its diverse assemblage of endemic species will respond is incomplete. www.nature.com , you need to pay close attention to the size of your tank and other important features. Different heaters will sit differently in a tank depending on the size and design of the tank itself. It’s also helpful to find heaters with longer cords. This will give you more flexibility in where your aquarium is placed than a shorter cord can offer.

You’re also going to need to pay close attention to the water composition of your tank (salt vs. freshwater) and the type of fish you own. Different fish species will require varying water temperatures to live comfortably. It’s important to ensure you have a heater that can accommodate their needs.

Important Features

Trying to find the right heater for your 20-gallon tank can definitely be stressful. After all, the temperature of your aquarium can literally mean life or death for your aquatic flora and fauna. Because of a heater’s importance, it’s essential to keep in mind tank compatibility, the power and temperature range, the size and weight of the heater, its adjustability, and any added costs for installation that may accrue.

Tank compatibility

5 Best Heaters for 20-Gallon Tanks - Versatile and Easy to Install!

Your tank’s heater is only going to be effective if it works with your specific tank.

The size of the heater in relation to your tank, along with the amount of power the heater can provide, will determine whether or not the heater you’re looking at is compatible with your aquarium. Each of the important features listed below ties into the level of compatibility a specific heater will have with your 20-gallon aquarium tank.

Power

Power is arguably the most important factor to keep in mind when shopping around. Without proper power, you risk uneven heating. For 20-gallon tanks, it’s important to get a heater that uses at least 50 watts. Any wattage less than 50 can result in an unevenly heated tank. If your heat is uneven, then your fish will become stressed, and they may die. Some heaters may come with varying models that accommodate different wattages. For example, our Editor’s Choice, the Orlushy Aquarium Heater, comes with five different models, each with different wattage allowances.

Temperature range

The temperature range an aquarium heater offers is also important because different fish and aquatic plant species need varying temperatures to survive and thrive. You’ll find that most heaters will accommodate at least 68-90 degrees Fahrenheit, but some will provide heating at temperatures with a greater range. Make sure to note your specific aquatic species before deciding on a heater.

Size

5 Best Heaters for 20-Gallon Tanks - Versatile and Easy to Install!

The size of your heater in relation to your tank is important because heaters need to be fully submerged in order to work. Suppose it’s too tall to stand upright or too long to lay flat.

You run the risk of the heater overheating and potentially exploding as a result. This becomes a fire hazard and can actually result in your dwelling catching fire. Even if you feel it will be fine to leave running outside of the water during tank water changes, leaving the heater running in dry air for even a minute can cause the glass to dry out and shatter completely. For this reason, we included the Mylivell aquarium heater as it’s more compact than most other 20-gallon tank heaters we’ve seen.

Weight

Depending on your setup, you should also take note of the weight of the heater. The heavier your heater, the more durable it usually is. Heavier aquarium heaters also generally mean they last much longer because of their durability.

A heavier heater may also mean it would suffice better to lay flat on the aquarium floor. This way, you don’t run the risk of the heater dislodging from the side suction and potentially breaking in the process.

Adjustability

Some aquarium heaters may have adjustable settings that allow them to become more compact or take up more space. They may also have adjustable settings in terms of temperature changing and automatic on/off settings. These are all important in making the heater more user-friendly and customizable to your specific fish tank. Adjustability is a big reason why we chose to include the FREESEA aquarium heater, as it’s easy to adjust the temperature settings with an external controller.

Installation place

If you aren’t confident in installing Trusted Source The effects of interacting with fish in aquariums on human health and well-being: A systematic review Review findings suggest that interacting with fish in aquariums has the potential to benefit human well-being, although research on this topic is currently limited. Future research should aim to address gaps in the evidence, such as whether and how the type of human-fish interaction can influence well-being outcomes. Researchers should also aim to address the methodological concerns highlighted in this review. www.ncbi.nlm.nih.gov the heater on your own, you’ll also need to factor in the cost of professional installation. Our top three picks on our list all come with free over-the-phone support where someone will walk you through the installation process via phone call.

FAQ

Installing a heater into your fish tank is relatively simple but should still be done so with extra precautions. Before you actually install the heater, you need to make sure you choose the right one for your tank. Make a mental note of the fish species you own and whether it’s a salt or freshwater tank. Jot down the temperatures you need and anything else worth remembering for the buying process.

Once you have the heater in hand, follow these steps:

1. Double-check the heater. Before installing, look over the heater one more time to ensure there aren’t any noticeable defects. If you notice any missing pieces or cracks in the glass, it’s important to return them to the seller right away. Failing to do so can lead to your tank overheating and your fish are dying.

2. Place the heater in the tank. It’s very likely that the heater also came with strong suction cups to help keep it in place. Whether you install it on the aquarium wall or on the floor, use the suction cups to ensure it isn’t loosely floating in the water.

3. Let it settle, then turn it on. Don’t turn the heater on immediately after installing. Let it rest for around 20 minutes to acclimate to the water before starting it up.

4. Adjust the temperature and leave it to work. Some heaters will have an external controller, while others will have a dial you turn to make temperature adjustments.

Fish tank heaters need to be completely submerged in water in order to work safely and effectively. If they aren’t completely submerged, the heater has a risk of overheating and catching fire from drying out. Most tank heaters have coils protected behind a layer of glass that heat up and disperse heat throughout your fish tank.

Our Verdict

Ensuring you find the best heater for 20-gallon tanks boils down to the type of tank you own and the species of flora and fauna you’re taking care of. From the temperature range to the adjustability of the heat temperature settings, finding the right heater for your needs is quite a task. If you’re looking for a heater that can easily be hidden on the aquarium floor, our Editor’s Pick of the Orlushy Submersible Aquarium Heater is perfect. If easy usability is more your speed, consider the FREESEA aquarium heater, our premium pick. For those on a budget, give the Hitop Adjustable Aquarium Heater a try. Whether you choose one of our awesome picks or go a different route entirely, we hope this detailed guide has been helpful for you.

References

1.
Water warming increases aggression in a tropical fish | Scientific Reports
Our understanding of how projected climatic warming will influence the world’s biota remains largely speculative, owing to the many ways in which it can directly and indirectly affect individual phenotypes. Its impact is expected to be especially severe in the tropics, where organisms have evolved in more physically stable conditions relative to temperate ecosystems. Lake Tanganyika (eastern Africa) is one ecosystem experiencing rapid warming, yet our understanding of how its diverse assemblage of endemic species will respond is incomplete.
2.
The effects of interacting with fish in aquariums on human health and well-being: A systematic review
Review findings suggest that interacting with fish in aquariums has the potential to benefit human well-being, although research on this topic is currently limited. Future research should aim to address gaps in the evidence, such as whether and how the type of human-fish interaction can influence well-being outcomes. Researchers should also aim to address the methodological concerns highlighted in this review.
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