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Best Aquarium Thermometer (2022 Review and Buyer’s Guide)

Every fish tank needs some method of telling you just what is going on inside. Not many people can simply guess by feel, so for the rest of us out there thankfully there are aquarium thermometers!

These handy devices come in a variety of styles, shapes, and sizes, and choosing can be a challenge for any home aquarist.

Whether you’re new to the market or looking for the latest and greatest, I’ve compiled a list of the best aquarium thermometer options out there today, so read on for my recommendations!

  • No probes or wires, simply stick on to your tank 
  • Accurate to within 0.1 degree Fahrenheit
  • Large, easily legible LCD display
Best Overall
  • LCD digital aquarium thermometer with suction cup
  • Simple operation and setup
  • Accurate to within +/- 2 degrees Fahrenheit
Best Value
  • Cordless stick on design
  • Accurate to within 2 degrees Fahrenheit
  • High and low temperature alarm
Editor’s Choice

The Best From The Reviews

Best Overall

Capetsma Aquarium Thermometer

This stick-on digital aquarium thermometer comes with a large, easily readable display and is incredibly accurate.

Capetsma Aquarium Thermometer

My choice for best all around option, the Capetsma digital thermometer not only has a high quality, large display but includes an onboard alarm for temperatures outside of your range.

This aquarium thermometer allows for peace of mind, along with quality construction.

Best Value

Aquaneat Aquarium Thermometer

This external digital pocket thermometer has a submersible temperature gauge which is very accurate for being such an affordable device.

Aquaneat Aquarium Thermometer

My pick for the most value, Aquaneat digital aquarium thermometers come with an attached probe that is placed in the water and attached to the tank via suction cups. This allows the reader itself to remain dry and out of the tank, making it ideal for a variety of applications from aquariums to terrariums.

Editor’s Choice

Hygger Stick-On Digital Aquarium Thermometer

The Hygger LCD digital aquarium thermometer has a premium set of features and good accuracy for such a small, unobtrusive display unit.

Hygger Stick-On Digital Aquarium Thermometer

Hygger designs aquarium thermometers with adaptability in mind. This option can be used for aquariums, vivariums, and terrariums, really anywhere you would want to place accurate aquarium thermometers. Easy to read LCD display, stick-on design, and a good range of temperatures make this my Editor’s Choice.

On To The Reviews…

Best Overall

Capetsma Aquarium Thermometer

This stick-on digital aquarium thermometer comes with a large, easily readable display and is incredibly accurate.

Capetsma Aquarium Thermometer

My choice for best all around option, the Capetsma LCD digital aquarium thermometer not only has a high quality, large display but includes an onboard alarm for temperatures outside of your range. This aquarium thermometer allows for peace of mind, along with quality construction.

Well Constructed

With a large, 3.2″ easily legible LCD display, this model comes with all of the modern features of many digital thermometers.

This stick on thermometer skips the troublesome suction cup in favor of an easy-to-use design that makes for simple and precise monitoring of the temperature in your tank.

The attached battery pack is removable, meaning you don’t need to unstick the entire digital thermometer to swap them out.

High/Low Alarm

The Capetsma LCD digital aquarium thermometer includes a built-in alarm that you can set to a particular high or low value, alerting you whenever your tank’s temperature goes out of the range.

This can be an incredibly valuable addition to an accurate thermometer, as it adds in another layer of safety for the creatures in your aquarium or terrarium.

Adhesion

Unfortunately this design is not meant to work with acrylic tanks. The design of most stick on thermometers such as this one prohibits it from adhering to the plastic material, and likewise curved or rounded structures will not work.

Additionally, the large size of the digital display unit on this model may mean that it does not fit for some smaller tanks.

Specs

  • Temperature range from 32-158 degrees Fahrenheit
  • Runs on two CR2 batteries (included)

Pros

  • No probes or wires, simply stick on to your tank
  • Accurate to within 0.1 degree Fahrenheit
  • Large, easily legible LCD display

Cons

  • Not recommended for use with acrylic tanks
  • Fairly large design may not be ideal for nano tanks

Best Value

Aquaneat Aquarium Thermometer

This external digital pocket thermometer has a submersible temperature gauge which is very accurate for being such an affordable device.

Aquaneat Aquarium Thermometer

My pick for the most value, Aquaneat digital aquarium thermometers come with an attached probe that is placed in the water and attached to the tank via suction cups. This allows the reader itself to remain dry and out of the tank, making it ideal for a variety of applications from aquariums to terrariums.

Wide Air and Water Temperature Range

As with many quality LCD thermometers, the Aquaneat has an incredibly wide range of temperatures.

The LCD readout is capable of detecting between -58 and 158 degrees Fahrenheit, with an accuracy of plus or minus two degrees. This means that for hot or cold set ups for a plethora of potential aquariums and terrariums you’ll get a good temperature reading.

Easy Setup

Attaches via suction cup to the inside of the fish tank. Simply immerse the temperature probe into the water and stick the suction cup to the aquarium glass and you’ll see an accurate reading.

Unlike stick-on thermometers, this option simply sits outside of the tank itself, with the probe measuring temperature in the aquarium water.

Temperature Reading

While two degrees one way or the other may not be a massive variation, it is still important to note that you’ll want to read as close to the correct water temperature as possible, be it warm or cold water.

Additionally, the cord based design means that you’ll need to contend with finding a good place to place the main body of the thermometer outside of your fresh or saltwater tanks.

Specs

  • Temperature range from -58 to 158 degrees Fahrenheit
  • Runs off of a LR44 battery (2 included)

Pros

  • LCD digital aquarium thermometer
  • Simple operation and setup
  • Accurate to within +/- 2 degrees Fahrenheit

Cons

  • Not quite as accurate as other models on the list
  • Limited range due to the cords

Editor’s Choice

Hygger Stick-On Digital Aquarium Thermometer

The Hygger LCD digital aquarium thermometer has a premium set of features and good accuracy for such a small, unobtrusive display unit.

Hygger Stick-On Digital Aquarium Thermometer

Hygger designs aquarium thermometers with adaptability in mind. This option can be used for aquariums, vivariums, and terrariums, really anywhere you would want to place accurate aquarium thermometers. Easy to read LCD display, stick-on design, and a good range of temperatures make this my Editor’s Choice.

Water Temperature Alarm

Easily visible on the LCD display itself, you can set a range of upper and lower water temperatures so that your digital thermometer can alert you when things are off.

Digital thermometers that possess this feature are some of my favorites because you never know when something like direct sunlight may be affecting the ambient room temperature around your tank.

Adaptability

Use these LCD thermometers anywhere you need a temperature reading. From water temperature to seeing the ambient temperature in the area, these are not just fish tank thermometers. The LCD screen can give you an accurate reading of water or air temperature wherever it is placed.

Accuracy

With a +/- 2 degree Fahrenheit accuracy, this option is not necessarily the most accurate when it comes to temperature reading.

This is not to say that the high and low temperature alarms won’t still tell you when the temperature drops or rises, but that it simply doesn’t have the thermometer accuracy of my overall pick.

Specs

  • Temperature range from 41-99 degrees Fahrenheit
  • Runs off of a 3V battery (included)

Pros

  • Cordless stick on design
  • Accurate to within 2 degrees Fahrenheit
  • High and low temperature alarm

Cons

  • Lower range compared to other options
  • Not the most accurate aquarium thermometer available

JW Pet Company Smarttemp Thermometer Aquarium Accessory

This simple to use analog thermometer is a great way to give some insight into the actual temperature in your fish tank without complications.

JW Pet Company Smarttemp Thermometer Aquarium Accessory

Analog thermometers may be less feature rich than some of the other options on this list, but they still absolutely have their place in today’s home aquarium. When you’re looking for a simple solution, analog is never a bad way to go.

Ease of Use

Simply place it in your tank and attach it with the included external magnet and you’re good to go, no need for a suction cup or sticky mess to clean up.

While the JW Pet Company Smarttemp may not have a fancy digital display or LCD screen, it does provide you with an optimum temperature range on the unit.

Accurate Readings

Given that the thermometer display itself is inside of the tank, you’ll be seeing an accurate measurement of your temperature ranges.

With an accuracy of +/-1.5 degrees Fahrenheit, you can tell when your tank is at a suitable temperature for your fish.

Features

Considering that this is an analog option, it will obviously be missing some of the more modern conveniences provided by digital thermometers.

No alarm for when the temperature rises or the temperature falls, no timers, just a simple way of telling what’s going on in your aquarium water.

Specs

  • Temperature range from 30 to 100 degrees Fahrenheit
  • No batteries required

Pros

  • Simple to use, easy to read
  • Optimum temperature range indicator
  • Accurate to +/-1.5 degrees

Cons

  • Missing many of the features of more modern aquarium equipment

Propagate Pro Thermometer Sticker Strips

This color-changing fish tank thermometer sticker strikes a good balance between function and simplicity when it comes to providing an accurate water temperature reading.

Propagate Pro Thermometer Sticker Strips

The Propagate Pro fish tank thermometer has a unique design when it comes to telling your tank temperature. Skip the suction cup and simply stick this sucker on your tank and you’re good to go!

Color Changing Temperature Gauge

This option comes with a unique color sensing system, which progresses from blue to green to tan as it reaches each temperature.

This allows the user to get a good idea of whether the temperature is increasing or decreasing at any given moment, or if you’ve reached a good equilibrium.

Simple Design

Why use suction cups when a sticker will suffice? Simply remove the backing from the adhesive cover and place it on the outside of any tank you’d like to gauge.

This particular option includes several stickers, so you can even place them at different points on your tank if you’d like to see temperature differentials.

Temperature Range

This model has a lower temperature range from 50-90 degrees Fahrenheit, which may not be too much of an issue for warmer tanks but can make gauging cold snaps difficult.

Additionally, each stick-on thermometer is single use, so you won’t be able to reuse them.

Specs

  • Temperature range from 50-90 degrees Fahrenheit
  • No batteries required

Pros

  • Simple in design and use
  • Color change to indicate temperature range
  • Comes in a pack of 5

Cons

  • Lower range of temperatures than other options
  • Each thermometer is single use

Keynice Digital Thermometer

One of the best aquarium thermometers on the market, the Keynice model comes with a high contrast display and accurate temperature scale.

Keynice Digital Thermometer

The Keynice thermometer has one of the best displays on the market, and is capable of detecting minute shifts in temperature and alerting you at a moments’ notice.

The incredible range of temperatures it can detect make it ideal for a variety of uses around the home.

Adaptability

With a range from -58 to upwards of 230 degrees Fahrenheit, this thermometer can be used for a variety of purposes.

From providing your optimal temperature range in an aquarium, greenhouse, or terrarium, this may be the best digital aquarium thermometer when it comes to versatility.

Design

This model comes with a high contrast LCD display and one of the best visibility among the digital thermometers on this list. Additionally it comes with USB rechargeability, meaning that you do not need to worry about battery life.

The small submersible probe size may be somewhat difficult to position properly in your tank. Getting creative with a clip, magnet, or sticker system can be a great optional workaround.

Specs

  • Temperature range from -58 to 230 degrees Fahrenheit
  • Powered via USB cable (provided)

Pros

  • High contrast digital display
  • Massive temperature range
  • Can be used for a variety of projects

Cons

  • Submersible probe can be tricky to attach

What is an aquarium thermometer?

Betta Fish Swimming in an Aquarium with Thermometer
Betta Fish Swimming in an Aquarium with Thermometer

An aquarium thermometer is any temperature gauge which can be used in an aquarium set up. These devices come in an array of designs including floating thermometers, submersible thermometers, or stick-on digital options.

What is the best aquarium thermometer?

When it comes to the best aquarium thermometer, there are a few key thermometer features that you should look for aside from simply telling the temperature inside your tank.

Accuracy

First and foremost, accuracy is the thing you’re looking for with any thermometer.

One with a wide range but low accuracy will not let you know exactly how things are in your tank, meaning that you can accidentally shock your fish with high or low temperatures, affecting their immune system function.

RECOMMENDATION

I recommend looking at the specs, and anything above a +/-2 degree accuracy range should be avoided.

Temperature Range

This can vary depending on the type of system you have developed. Some people, such as those with tropical fish may be able to get away with a model with a lower range, provided that the thermometer can display at least the warm tank temperature their fish need.

For those with colder set ups than tropical fish or those looking to use one outside of their aquarium, a wider range may be desirable.

Display Type

Digital, analog, and sticker are the primary types of display available. Unless you’re looking to save money or purchase multiple thermometers for use around the house, a digital display is going to be the easiest to read and likely comes with a more accurate system on board.

NOTE

The best aquarium thermometers on this list tend to have LCD displays that contrast with the tank.

Attachment Style

Several of these options are stick ons, while others may use a suction cup and have a separate detection method. Not mentioned on this list but still an option is the marina floating thermometer, which works best in ponds or tanks without much water movement.

Where is the best place to put a thermometer in a fish tank?

Fish Tank with Rocks and Reefs
Tropical Coral Reef Aquarium

While this depends somewhat on the type of attachment system (probe, sticker, suction cup, marina floating thermometer, etc) there are some more ideal placements in your tank.

For the options on this list, aiming around the midpoint of your aquarium away from the substrate and surface (which may be warmed unevenly) is the best way to go.

How do I know if my aquarium thermometer is accurate?

Using more than one thermometer to check another is not a bad idea here. When it comes to tank safety, ensuring that your tank’s temperature is reading properly can mean the difference between survival and death for your fish.

A good test of accuracy is to place it in a glass of ice water and wait at least 15 seconds. After some time has passed, you should see a temperature reading of 32 degrees. If not, you know that something is off!

Here’s a video on how to check thermometer accuracy.

How to check fish tank thermometer accuracy!

How do I calibrate my aquarium thermometer? 

Some models may have slightly different methods prescribed by the manufacturer, but the previously described “ice water method” works quite well in calibrating your thermometer especially for a floating thermometer.

NOTE

You’ll want to recalibrate at least twice a year, to ensure maximum accuracy.

Conclusion

I hope that you’ve enjoyed these reviews and found the best thermometer that works for your personal aquarium setup. While there are a lot of options out there, some options may suit your needs better than others.

If you still haven’t decided, here are a few last minute tips.

  • No probes or wires, simply stick on to your tank 
  • Accurate to within 0.1 degree Fahrenheit
  • Large, easily legible LCD display
Best Overall
  • LCD digital aquarium thermometer with suction cup
  • Simple operation and setup
  • Accurate to within +/- 2 degrees Fahrenheit
Best Value
  • Cordless stick on design
  • Accurate to within 2 degrees Fahrenheit
  • High and low temperature alarm
Editor’s Choice

Best Overall

My choice for best all around option, the Capetsma digital thermometer not only has a high quality, large display but includes an onboard alarm for temperatures outside of your range.

This aquarium thermometer allows for peace of mind, along with being made of quality materials that will last.

Best Value

My pick for the most value, Aquaneat digital aquarium thermometers come with an attached probe that is placed in the water and attached to the tank via suction cups.

This option has all of the features of my more expensive picks at a portion of the price, proving you don’t need to break the bank for utility when it comes to covering the basics.

Editor’s Choice

Hygger designs aquarium thermometers with adaptability in mind. This option can be used for aquariums, vivariums, and terrariums, really anywhere you would want to place accurate aquarium thermometers.

Easy to read LCD display, stick-on design, and a good range of temperatures make this my Editor’s Choice.

Thanks for Reading!

I hope you’ve found this article helpful in choosing the best liquid thermometer for displaying the temperature inside your aquarium.

As always feel free to share this article with any other fish fanatics you know, and I wish you the best of luck on your continued aquarium adventures.

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Mollie Newton
Mollie Newton
Founder of PetMeTwice. I love all types of animals from fish to fluff-balls! I also enjoy writing short stories and helping train animals 🤩