Best Aquarium Thermometer: Buying Guide and Top list

Carol M.
Fisheries Consultant

As a fish keeper, there are tools that you require for proper fish monitoring. One essential tool that you need is an aquarium thermometer. This tool helps maintain the correct water temperature for your fish. With a thermometer, you can measure water temperature in the aquarium and adjust it accordingly. So, what type of thermometer is best for your aquarium? Below is a buying guide to help you choose the best thermometer for your aquarium.

Top 10 Aquarium Thermometers to Consider

Some of the best thermometers you can consider are as follows;

1. Cooper Atkins DFP450W Digital Thermometer

The thermometer is small, compact, and waterproof, thus ideal for aquarium use. It's very accurate, and people prefer to double-check other thermometer readings. You should dip the probe inside the tank and get accurate readings within -40-450 degrees F. Cooper can also switch between Celsius and Fahrenheit.


  • Extremely accurate
  • Perfect for water changes
  • Pocket size and portable


  • It can't be left permanently in the aquarium

2. Zacro Pack Digital Thermometer

The thermometer has a large LCD, thus easy to read. It gives accurate readings within a +/-  0.1 degree. Zacro is unique as it features a suction cup that you stick on the aquarium and a submersible probe. It uses a single long-lasting LR44  battery.


 You can get the readings either in Celsius or Fahrenheit, within a temperature range of -50 to 70 degrees Celsius. Attach the suction cup, display it outside the tank, and immerse the probe in water to get your water readings. Then hold the power button to turn on, and take your readings.


  • It’s convenient to use with a submersible probe.
  • A wide temperature range and accurate readings
  • Simple to use and install
  • Large LCD for easy reading
  • Powered by a single LR44 button cell battery


  • The suction cup may lose suction with time
  • Loose battery connection
  • Only the probe unit is waterproof.

3. LCR Hallcrest A-1005 Thermometer

LCR is accurate, and you mount it outside the tank and take temperatures. This thermometer shows a change of colors to show where temperature lies and indicate whether water has the correct temperature. Again, the tool features large fonts for easy reading. The thermometer requires no battery or wiring to operate, thus becoming easy to use anywhere, and it's also durable.


  • Highly accurate
  • Easy to read
  • Suction power for adhesion


  • Hard to read without a flashlight/direct light
  • Must be close to the thermometer to see the numbers

4. Vivos LCD

This thermometer has a large LCD enough for someone with vision issues. It comes with an extra cable that is long and easy to adjust. Again, it has two suction cups for attaching, thus, securing the device. Vivos comes with a long-lasting replaceable battery, making it convenient to use. It can take readings between -50 to 7o degrees centigrade with a precise result of within +/- 0.1 degrees.


  • Wide temperature range
  • High accuracy of +/-0.1 degrees


  • Plastic cups may lose strength
  • It’s made of plastic materials

5. JW Pet Company Smarttemp Thermometer

JW is a simple thermometer that is 7 inches tall. It has mercury and a magnetic fastener that holds it into place. It has large numbers on its scale that you easily read and green marks or an ideal temperature range in a tropical aquarium. The thermometer is accurate within 1.5 degrees and has an enormous fault than other thermometers. When taking readings, dip the thermometer inside the tank, and secure it with a magnet on the outside.


  • It’s very affordable
  • It uses a magnetic fastener
  • Large numbers for easy reading
  • Requires no power to operate


  • It has a more significant fault
  • Glass is delicate thus can break

6. Aquanaut 1-Pack Thermometer

You use this thermometer in various environments like an aquarium, terrarium, and different types of waters such as fresh, salty, marine. It comes with a large LCD for easy reading. This thermometer uses a battery and comes with a free LR44 button cell and a spare one. It has a wide temperature range of  -58 to 158 degrees F, with an accuracy of +/- 1 degree Celsius.


  • Ideal for use in water and high moisture environment
  • Large LCD for easy reading
  • It has a suction cup for set-up


  • Readings aren’t accurate as in other thermometers

7. Carpets Touch Screen Thermometer

The carpet is very user-friendly with a large clear LCD of 3.2 inches from side to side. This feature makes it easy to take readings even from a few feet away. The device is wireless with 3 inches by 3 inches dimensions. All you need is to attach it to the tank and take the readings through the glass. 

It's accurate within less than 1 degree and uses both temperature measuring units. The unit flashes once the tank readings are outside the set range. This device may fail to attach to plastic tanks, and even in glass ones, it may be difficult to remove it.


  • Accurate with a fault of less than 1 degree.
  • It’s wireless
  • It has a clear display that blends with your tank
  • Flashes when readings are outside the set range
  • Touchscreen capabilities


  • Fails to work on plastic/ acrylic tanks
  • It's difficult to remove when attached to a glass aquarium

8. Marina Floating Thermometer

You may consider this thermometer when working on a tight budget. The device requires no power or battery to operate, thus convenient to use anytime. This thermometer is wireless, but you have to attach it to the tank with a suction cup. 

As from the word floating, you do not always require a suction cup as it floats vertically in the tank. It uses a red-dyed solution to show the temperature of your tank. This device is 4 inches tall and takes readings within ½ inch around.


  • It’s wireless
  • Requires no power to operate
  • Floats vertically on water


  • Font readings are small thus tricky to read
  • Its green range isn’t accurate for some tropical fish

9. Marina Deluxe Thermometer

Marina is a liquid thermometer, wireless, and requires no battery to operate. It's easy to use with a suction cup to attach and submerge in water. This thermometer has colors to indicate whether the temperature is within the correct zone. You can use this thermometer for both fresh and salty water aquariums.


  • It’s very cheap
  • Gives accurate readings
  • Requires no power source to operate.


  • Flimsy suction cup
  • The markings are small for someone with sight issues

10. Sungrow Digital Thermometer

This thermometer is lightweight, durable, and easy to use. The device features suction cups for attachment to the tank. It has a sizable shiny display that makes reading easy even in the dark. It's preferred for betta fish to maintain their tropical habitat. It has a range of -58 -158-degree F and is very accurate. It's made of plastic, thus ensuring the temperature isn't affected.


  • The screen reader is visible and easy to read
  • Resilient to room temperature changes
  • Better accuracy than floating thermometers
  • It’s durable


  • Its low quality compared to other thermometers

What to Look for When Choosing an Aquarium Thermometer?

When choosing a thermometer, there are factors you should consider, as explained below:

  • Accuracy and Range

When taking the water readings, accuracy is key and should have at least +/- 1 degree Celsius range. Some fish species are sensitive to water temperatures, requiring an accurate thermometer. So, it’s best you consider an accurate thermometer with a wide range ideal for the tank. The best range to choose from is between 50- 104 degrees F.

  • Temperature Readability

A thermometer will be useless if you can't read the temperature. A thermometer with a large LCD and a probe would serve better for readability.

  • Durability

Choose a thermometer that is long-lasting; it will be worth the investment. A delicate device might break inside the tank, and if using mercury, it may release harmful chemicals to your fish. Again, consider one that has long-lasting battery life.

  • Safe for Your Fish

Choose a thermometer that is safe for your fish. It should have non-toxic and non-chemical leaching. If made of glass, it should be shatter-proof.

  • Ease of Use

The thermometer should be easy to use without any complicated configuration. If you use a complex gauge, it may take longer to mount and measure the temperature.

  • Type of Thermometer

Choose a thermometer that fits your budget as well as your aquarium needs. There are three main thermometers; digital, standing/ floating, and stick-on. Digital thermometers are accurate while standing, are easy to use, and are suitable for large tanks.


The best thermometer helps you take readings and maintain a favorable temperature for your fish. Again, it will protect your fish from severe water quality issues that may result from unsuitable temperatures. This guide has given you the best ten thermometers you may consider if you need a thermometer. Remember to follow the above factors to ensure you acquire the best thermometer.

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