Best Thermometers for Your Fish Tank

Best Value for Money Thermometers for Your Fish Tank

The most important part of keeping an aquarium is that you have all the essential equipment needed to maintain the health of your aquarium fish.

The most necessary equipment that you must have is aquarium thermometer. For the survival of fish, maintaining correct temperature is very optimal. If not maintained properly the fish could die.

There is a wide range of thermometers in the market but you need to choose the best for your aquarium.

To help you out, we’ve come up with this essential buying guide that covers top 5 aquarium thermometers with their pros and cons.

Fishes are very tender creatures and when taken care of in the fish tanks need to be provided with the best environment to breed. They have their life connected directly to water and thus the water condition is a vital part of a healthy fish tank.

Refer to the following articlesBest Gravel Cleaner & Best refugiums Reviews

 Though, there are many things to take care of in a fish tank like size, companions, water type and similar habitat, the temperature of the tank is the most sensitive one and need to be observed most of the time.

If you need to cool your tank, also look at our reviews of best water chillers for aquarium.

What Does an Aquarium Thermometer Do?

A thermometer is basically a device that is used to measure the water temperature of the aquarium.It’s very important that the aquarium water remains within a specific temperature range.

The optimal temperature range generally varies according to the need different kinds of fish or other aquatic creatures you keep in your aquarium.

Having a thermometer in your tank will make sure that everything will keep on running smoothly.

How to know the ideal temperature for your tank?

Fishes come from different regions all around the world and may want different kinds of temperatures, so firstly take a note of the kind you bring in.

They should have less than 5 degrees of temperature margin to become habitual of the environment altogether.

However, the most common pet fishes align well between the ranges of water temperature being 23-28 degree Celsius. Keeping the temperature constant or least varying is important for a healthy fish.

Factors to Consider When Choosing a Thermometer for Aquarium

  • Easy Installation
  • Accuracy
  • Range
  • Durability
  • Temperature Readability

It is very important to check the setup and installation process of any equipment you use. Though most of the thermometers are very simple to use but still you should check this factor during buying it.

Make sure that the thermometers work in a proper manner. Otherwise, it can lead to the death of fish.

Ideally, you should choose a temperature that gives the readings in a range from 50 to 104 degrees Fahrenheit.

The best aquarium thermometer always comes in durable-quality and works efficiently for a long-lasting time.

Look for a thermometer with a big and clear display that’s easy to read.

Below Are the List Of Top 4 Thermometers for Your Fish Tank

There can be many types of thermometers and they all work fine. But, the compatibility depends on your needs and the time you dedicate to the maintenance of the fish tank.

 You can get from a basic dip thermometer to a permanent sensor thermometer with advanced danger alarm sensors. The prices vary accordingly but none of them will empty your pockets or hurt you much. 

Here are some of the best thermometers available in the markets which give the most value for your money.

1. Marina Floating Thermometer with Suction Cup

Marina Floating Thermometer for Betta Fish Tank with Suction Cup, Aquarium Thermometer, 11201A1
  • Easy to read floating aquarium thermometer with suction cups
  • Includes a safety zone indicator appropriate for most tropical fish
  • Equipped with suction cups to attach to the side of your fish tank
  • Ensures your aquarium is at the proper temperature
  • Thermometer is 4.25 inches tall

Last update on 2021-12-13 / Affiliate links / Images from Amazon Product Advertising API


  • It is a very easy-to-read floating thermometer that comes with suction cups.
  • It also includes a safety zone indicator.
  • It effectively works in maintaining the optimal temperature in thermometer.
  • Works accurately and very easy to use.
  • This thermometer also has a safety zone temperature range indicator.
  • It works perfectly in both freshwater and saltwater aquariums.


  • Users complained that it’s suction cups contain chemicals.
  • It also gives a very strong industrial chemical plastic smell.

This one serves the best for permanent thermometers. Without any electronic features, it simply works on the principle of temperature expansion of the material which is used as indicator.

Old style analogue reading scale is a little downfall for the ones who do not know how to read temperatures. The body work is leak proof and the looks are good enough to work as a fish tank decor too.

2. HDE Digital Aquarium Thermometer Fish Tank Thermostat Water Temperature Control

HDE LCD Digital Fish Tank Aquarium Thermometer Terrarium Marine Temperature (Black)
  • Large easy to read display with easy to apply suction cup for secure convenient placement
  • Submerge probe in to water to measure the aquariums temperature (Do not submerge the display)
  • Accurate temperature readings to within 0.1 degree | Temperature range -50°c~ + 70°c. Operating temperature -10°c~ +50°c
  • Includes LR44 Batteries | Size of unit: 2" x 1.25"
  • Package Contents: 1 x Battery; 1 x Digital Thermometer; 1 x Probe

Last update on 2021-12-13 / Affiliate links / Images from Amazon Product Advertising API


  • This is a large-sized and very easy to read thermometer with easy to apply suction cup for secure convenient placement.
  • It always shows the most accurate reading.
  • Includes LR44 Batteries.
  • It easily sticks with the glass of the aquarium.


  • Some customers complained that it stops working after the use of a few months.

Wired digital thermometer has one advantage over others as the indicator meter does not get immersed into the tank thus increasing its life span.

The detecting gauge can be replaced for less than $2 when required. Battery backup is good when it comes to digital thermometer working 24*7.

3. Zacro LCD Digital Aquarium Thermometer Fish Tank Water Terrarium Temperature

Zacro LCD Digital Aquarium Thermometer Fish Tank Water Terrarium Temperature
  • Submerge probe into fish tank to measure water temperature (Submerge probe only, do not submerge thermometer in water)
  • Easy to apply suction cup and easy to read LCD screen; Temperature readings to within 0.1 degree
  • Large, easy to read LCD display. Compact design for discrete use
  • Temperature range -50 degree Celsius~ + 70 degree Celsius; Operating temperature -10degree Celsius~ +50degree Celsius
  • Powered by one LR44 button cell (included)

Last update on 2021-12-13 / Affiliate links / Images from Amazon Product Advertising API


  • It is very easy to apply a suction cup.
  • It comes with a large, easy to read LCD display.
  • It offers a compact design for discrete use.
  • It is powered by one LR44 button cell.
  • It is small in size, easy to hide, and can be easily turned on and off to save battery.
  • No odor of chemicals and no rubber on the parts.
  • Works fantastic for a betta tank.


  • Some users complained that it takes too long to show an accurate reading.

The cost may hike up a little as compared to other digital thermometers without much brand value, but this one proves its mettle all the time.

The casing is efficient and works best among the digital thermometers. It gives accurate readings in both salt and fresh water tanks.

4. Zoo Med Digital Thermometer

Zoo Med Digital Terrarium Thermometer, 3 x 2 x 1&quot
  • Specially designed to accurately measure terrarium temperatures in Fahrenheit or Celsius.
  • Simple and easy to see LCD screen displays accurate temperature readings with no cumbersome settings or buttons.
  • The water-proof remote sensor probe lets you check the temperature in dry or wet substrates.
  • Easy to set up and install anywhere on your terrarium without obstructing your view.
  • You can use it out of the package with no assembly or programming; includes battery.

Last update on 2021-12-13 / Affiliate links / Images from Amazon Product Advertising API


  • Its external sensor can go in the water.
  • It shows clear LCD readout.
  • It is battery powered.
  • It is super easy to figure out it’s working.
  • It is practically ready to use as soon as you open the packaging of the product.
  • This product is available at a very affordable price.


  • The suction cup on the readout box doesn’t hold very well always.
  • The screen is not bright enough.

The manufacturer of this product is famous because of such good reviews especially from the new fish tank enthusiasts who have less knowledge.

The ease of use and features are tremendous for such a simple thing. This product will give you an imaginary onetime investment assurance because of great long term work efficiency.

My Pick

So there you have it, 5 of the best fish tank thermometers available in the market. All of them works great and have some unique features that make them different from each other.

In my opinion, Zacro LCD Digital Aquarium Thermometer Water Terrarium Temperature is the best one. This is because its design is compact and it is very easy to use.

In addition, it runs on a long-lasting battery and gives a clear view of the temperature. Anyone with a genuine budget can easily buy and use this thermometer.

Happy fish keeping!


[Revised and Updated for July, 2019]
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Written by Debra Hutchinson, founder of FishXperts

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