The Best Aquarium Heater For 5 Gallon Tank: Ultimate Guide!

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I have been an aquarist since childhood, and I have three aquariums currently at home. So I’m confident in helping you choose the right aquarium heater for your 5 gallon tank.

If you’re short on time, feel free to jump to my top picks listed below. Instead of overwhelming you with too many options, I have carefully chosen the two best aquarium heaters of each type. 

Key Highlights:[Our Top Pick][Runner’s Up]
Heater:AquaMiracle Aquarium HeaterOrlushy Aquarium Heater
Type:Adjustable Aquarium HeaterPreset Aquarium Heater
Wattage:25W – Suitable For 5 Gallon Tank25W – Suitable For 5 Gallon Tank
Author’s Note:Compact And Feature-RichSuitable For Betta Tank
Price:Check Here (on Amazon)Check Here (on Amazon)

But if you’re looking for more in-depth guidance, keep reading for my detailed reviews and advice on this topic.

Factors To Consider When Buying A Heater For A 5 Gallon Tank

  • Appearance
  • Size
  • Ease Of Operation
  • Temperature Adjustability
  • Indicators

What To Expect When Buying An Aquarium Heater For A 5 Gallon Tank?

When you’re in the market for an aquarium heater for your 5 gallon tank, it’s important to keep your expectations realistic. You may not find popular brand names like Fluval, Eheim, and Hygger, as their heaters are designed for larger tanks.

Instead, you’ll likely come across heaters from lesser-known brands. But don’t worry, a good aquarium heater for a 5 gallon tank doesn’t have to be a big brand name.

As long as it’s effective, easy to install, looks great, and has positive response from other aquarium owners, it’s a great option!

With that in mind, I’m excited to share with you my top picks for the best 5 gallon aquarium heaters. But before that, it’s crucial to have an understanding of the various types of aquarium heaters available when searching for a 5 gallon tank heater.

Adjustable vs. Constant Temperature Heaters – Know The Difference Before You Buy

One type of heater is adjustable, meaning you can manually set the temperature to your preferred level using a knob or controller. The heater will then work to maintain that temperature range.

On the other hand, you may also come across constant temperature or preset heaters. These heaters are pre-programmed with a specific temperature, typically around 78°F, and will automatically maintain that temperature range without any manual adjustment.

While both types of heaters can effectively heat a 5 gallon tank, adjustable heaters are more preferable because they offer greater control and flexibility.

With an adjustable heater, you can customize the temperature to suit the needs of your specific fish species. Plus, as the temperature needs of your tank change over time, you can easily adjust the heater accordingly.

However, if you’re looking for a straightforward, “plug-and-play” option with predetermined temperature settings, you may find that preset aquarium heaters are more preferable.

So overall, the choice between an adjustable and constant temperature heater ultimately comes down to personal preference and the specific needs of your aquarium.

#1. AquaMiracle Aquarium Heater – The Best Adjustable Aquarium Heater For 5 Gallon Tank

AquaMiracle® Adjustable 25W Aquarium Heater Submersible Fish Tank Heater Super

What I Like:

One of the most impressive things about the AquaMiracle heater is its compact size. At only 4 inches in length, its 25W heater takes up minimal space in small tanks. This is an essential consideration, as you don’t want a heater that dominates the tank and distracts from the overall aesthetic.

Another standout feature of this heater is its digital display thermostat. It reads the temperature of the aquarium, displayed in red colors, which looks pretty cool. This unique feature sets it apart from other aquarium heaters on the market.

Furthermore, this aquarium heater boasts excellent temperature accuracy. Its inverter technology and advanced built-in chips work together to maintain a consistent temperature in the tank.

What I Didn’t Like:

The only drawback of this heater is that the cord between the heater and digital thermostat is a little short. However, with a bit of maneuvering, you can use the product without any significant issues.

Pros And Cons

Adjustable And Digital Temperature Reading DisplayedShort Cord Length
Remembers The Temperature Settings
Low Water Level Protection Available
Overheating Protection Available


  • The 25W aquarium heater is ideal for use in 5 gallon tanks.
  • Equipped with a digital thermostat, which displays temperature readings and allows you to set the desired temperature at the touch of a button. This is a great alternative to rotating knobs that require careful monitoring while setting the desired temperature.
  • The digital thermostat also includes indicator lights that display the heater’s status in red and green colors.
  • Uses inverter technology and advanced chips to maintain a constant temperature in the tank with an impressive accuracy of around 1°F.
  • Features dry run protection, which automatically turns off the heater when the water level drops to the minimum level to protect it from damage.
  • The heater also includes overheat protection, which prevents extreme heat that can be fatal to aquarium fish. Sensors in the heater automatically turn it off when the temperature exceeds 97°F.

Who Shouldn’t Buy?

If you prefer traditional knob-based adjustable aquarium heaters, then the AquaMiracle heater may not be suitable for you. In that case, the Uniclife adjustable aquarium heater available on Amazon, which also comes with a thermometer strip, could be a better option for you.

Uniclife Aquarium Heater 25W/50W/100W/200W Adjustable Submersible Heating Rod with Electronic

Another reason to skip the AquaMiracle aquarium heater is if you prefer preset temperature aquarium heaters. If you’re looking for such heaters, keep reading as the next heater in this guide is a better fit for you.

Who Should Buy?

If you are looking for an adjustable aquarium heater for a 5 gallon tank that gives accurate readings and also comes with a digital display for checking the temperature readings, then look no further than the AquaMiracle aquarium heater.

Check The Latest Price Here (on Amazon)

#2. Orlushy Aquarium Heater – The Best Constant Temperature Aquarium Heater For 5 Gallon Tank

Orlushy 25W Small Submersible Aquarium Heater, Constant Temperature Betta Fish

What I Like:

One of the most striking features of the Orlushy Aquarium Heater is its sleek and compact design. With a length of only 4.7 inches, it won’t take up much space in your 5 gallon tank.

Secondly, I really love the durable feel of this aquarium heater. Thick glass is used in its construction and the entire heater is covered with a heat-resistant protective shell made from ABS material.

Additionally, this aquarium heater comes equipped with essential features such as an indicator light to show its working status, as well as a strong suction cup for easy attachment to the tank wall.

What I Didn’t Like:

One drawback I found with this heater is that it’s a preset heater, meaning you can’t adjust the temperature that comes with it. However, if the preset temperature is suitable for the fish species in your tank, then it shouldn’t be a problem.

For your reference, here’s a list of common aquarium inhabitants and their appropriate temperature ranges.

Aquarium Fish:Temperature Range:
Betta Fish75-80°F
Neon Tetra72-78°F
Guppy Fish72-82°F
Molly Fish75-80°F
Red Cherry Shrimp77-81°F

As you can observe, the preset temperature range of this Orlushy heater is suitable for all the tank species mentioned in the above chart since it falls within their optimal temperature range.

Pros And Cons

Compact DesignNot An Adjustable Heater
Durable Material
Suction Cups For Easy Installation
Indicator Light To Know The Status


  • With its sleek black finish and 4.7-inch length, this heater is a great fit for 5-gallon tanks, taking up minimal space while adding to the tank’s aesthetic appeal.
  • The heater comes preset at 78°F, which is within the optimal temperature range for most common species of fish, making it incredibly user-friendly. The heater is quite easy to operate – once submerged, attached to the tank wall, and plugged in, it will begin to work automatically.
  • The heater is constructed with durable ABS material that can withstand exposure to heat without melting. The heating rod is composed of nickel-chromium wire within a quartz glass structure.
  • The heater has an indicator light that displays its status in two colors: red indicates that the heater is actively heating the water, while green signals that the temperature has reached 78°F and the heater is maintaining the desired water-temperature.

Who Shouldn’t Buy?

Not interested in a preset aquarium heater and prefer an adjustable option? Then the Orlushy aquarium heater may not be the right choice for you.

Additionally, if the fish species you have requires a different temperature range than the preset 78°F, this heater may not be the best fit. For example, fancy goldfish require a temperature range of 68-74°F, which falls outside of the preset range.

Who Should Buy?

If you’re a beginner or prefer a straightforward, plug-and-play heater that doesn’t need adjustments, the Orlushy aquarium heater is a great option. It’s particularly suitable if you have betta fish or other species that thrive in a temperature range closer to 78°F.

Check The Latest Price Here (on Amazon)

How Many Watts Of Aquarium Heater Do You Need For A 5 Gallon Tank?

A common guideline for selecting the appropriate wattage for an aquarium heater is to use 2.5W-5W heater per gallon based on the tank size.

Therefore, for a 5 gallon tank, you would require an aquarium heater with a wattage of 12.5W-25W.

Do You Really Need A Heater For A 5 Gallon Tank?

Absolutely, having a heater for a 5 gallon fish tank is highly recommended to ensure your fish thrive and stay healthy.

Maintaining a consistent and appropriate temperature is crucial for the well-being of fish. Most fish species have a specific temperature range in which they thrive, and failure to provide the correct temperature can lead to stress.

For instance, Betta fish have an ideal temperature range of 75-80°F (23.8-26.6°C), while Discus fish prefer a temperature range of 82-86°F (27.8-30°C). Without a heater, the temperature of the water can fluctuate, and sudden changes in temperature can cause stress and shock to the fish, which can lead to sickness and even death.

An aquarium heater plays a vital role in maintaining a constant temperature in your fish tank, regardless of the external temperature fluctuations. It ensures the water temperature remains constant and optimal for your fish.

Therefore, it’s highly recommended to invest in a quality aquarium heater to ensure your fish thrive in a healthy and stress-free environment.

Can You Use A 50W Heater For A 5 Gallon Tank?

Typically, a 50W heater is more powerful than what is required for a 5 gallon tank. While there is no harm in using a heater that is too powerful, there are some risks to keep in mind.

Firstly, a powerful heater can heat up a tank more quickly, which can be stressful for fish due to the sudden temperature rise.

Modern heaters are equipped with thermostats that will turn off once the desired temperature is reached. But the problem is that the heater will turn on again once the temperature drops, creating a constant on and off cycle that could cause malfunctioning issues in the heater.

In addition, if the heater malfunctions and stays on, it could be disastrous for the fish – fish will likely die even before you could sense the issue. This is where using a small aquarium heater that’s appropriately sized for the tank comes in handy. You’ll at least have some time to identify and fix any issues that arise.

In short, if you do choose to use a more powerful heater, make sure to purchase from a reliable brand to minimize the risk of malfunctions.

Ultimately, it’s best to pick an aquarium heater that is adequately sized for the tank. For a 5 gallon tank, a heater with a capacity of 25 gallons would be a safe and reliable choice.