Best Aquarium Thermometer in 2020 – For Water Temperature

There are different types of fish that you can keep in your aquarium, and some are sensitive to heat and cold. When you have such fish, you cannot depend on the heating system of your house. You need to get an aquarium thermometer so that it will be easy for you to check and adjust the temperature in the aquarium effectively.

You might think that the tank is just, but when there is unsuitable water temperature, this can have adverse effects on the fish and plants in the aquarium. This requires you to purchase a very durable and dependable aquarium thermometer to check the water temperature.

When you are picking an aquarium thermometer, it is advisable to look for the best model on the market so that you do not end up with a thermometer that can break inside the aquarium. The thermometers contain mercury and other lead based substances that can affect your fish if they break.

Top 11 Aquarium Thermometer - Comparisons

Here are some top quality thermometers that are best for any aquarium. With any of these devices, the water temperature in your aquarium will be at its best.

11 Best Aquarium Thermometer Reviews

It is very important to maintain a stable temperature that should be ideal for the type of fish that you have. Aquarium thermometers do not cost much so you should consider buying one if you have an aquarium.

The CNZ Digital LCD Thermometer is an amazing device that you can purchase to monitor the temperature levels in your aquarium. You will love the accuracy of this thermometer when measuring temperatures within +/- 1.5 F of the real temperature.

The thermometer works well in any tank, and it has an easy to read the display when you need to know the temperature inside the tank. It has a display that you can set up either to get the readings in Celsius or Fahrenheit. This device is also durably made as compared to other units, so it will provide you with a long lasting performance.

It comes with a replaceable battery, and this means that your creatures in the aquarium will not experience shock from something plugged in. This device is made with high-quality materials that cover it to prevent water from damaging the inside of the unit.


  • It is easy to set up
  • It has a durable make
  • Provides accurate water temperature readings
  • The LCD display is easy to read
  • Comes with a replaceable battery
  • Works well with aquariums and terrariums
  • Measures temperature in both Fahrenheit and Celsius


  • The durability of the screen is questionable

To come up with a comfortable environment for the creatures in your aquarium, it is important to get the right aquarium thermometer that will help you check low and high temperatures in your aquarium.

With the KollerCraft TOM Temp Alert Digital Thermometer, you can use it in both freshwater and saltwater aquariums. This thermometer has a temperature alert to let you know a drop in temperature. It alerts you through an audible and LED alarm.

It presents a low temperature of 75 degrees F and a high temperature of 82 degrees F. The thermometer comes with suction cups that help you to stick it on the outside of the fish tank. It also has a long 3-foot cord that makes it easy to place it anywhere you want.

Users of the thermometer love the accurate readings that it provides. You will always know the right temperature unlike in other thermometers that provide false temperature readings.


  • Convenient and easy to use
  • It provides accurate readings
  • Perfect for both fresh and saltwater aquariums
  • Comes with a 3-foot long cord
  • Has audible and LED notifications for temperature fall and rise
  • It is durable


  • Temperature is off like 3 degrees

As compared to other housepets, fish require a lot of attention, and this involves maintaining the right environment for them. How do you ensure that the fish in your aquarium are comfortable?

The answer is simple, get HDE Digital Aquarium Thermometer, and it will be easy for you to monitor the water temperature in the fish tank.

The HDE Digital Aquarium Thermometer sticks with ease on the walls of the glass of the aquarium to provide accurate temperature readings in both Fahrenheit and Celsius measurements. It has a temperature range of -50 degrees to 70 degrees and an accuracy of 0.1 degrees.

Setting up the device is pretty simple because you only have two components that is the sensor and the display. Each of the ends are designed with a suction cup that is attached to provide a secure fit to the aquarium. Ensure that you submerge the sensor end in the water to get the right temperature reading.


  • Has a large easy to read display
  • The temperature reading is accurate to within 0.1 degree
  • Features suction cups for easy installation
  • Easy to use and install
  • Comes with LR44 batteries


  • Not long lasting

The majority of fish require a specific water temperature to ensure that they are comfortable. The only way in which you can determine the ideal water temperature for the fish is having the best aquarium thermometer.

This will help you monitor the water temperature and keep your fish in their best state.

To achieve this, you need to get the CoZroom LCD Digital Aquarium Thermometer that is designed with a clear LCD display for easy reading.

This is a compact and small aquarium thermometer that is easily portable. It is powered by two batteries, and it installs with ease. You just need to attach the display outside the fish tank using the suction cups then submerge the probe into the water.

This thermometer is durably constructed with a sturdy plastic material to provide a long lasting performance. It can also support a variety of environments with a temperature range from -50 to 70 degrees.

The accuracy of the thermometer is another great aspect. It brags of a high accuracy of 0.1 degrees, and this ensures that the water temperature is exact for the fish. You can easily see the temperature readings on the LCD display.


  • It has a sturdy plastic construction
  • It is easy to install with the suction cups
  • The temperature reading is accurate
  • The LCD display provides easy temperature reading
  • Small and compact making it portable
  • Works well in different environments


  • Not ideal for precision

Having an aquarium thermometer is useful if you have a fish tank. You need to ensure that the fish are comfortable and have the right temperature that is neither too low nor too high. A good aquarium thermometer should provide you with accurate temperature readings.

This is why you should invest in a quality product like the Zacro LCD Digital Aquarium Thermometer for the best temperature monitoring.

The thermometer is designed with an LCD display that is easy to read. It displays the temperature reading in either Celsius of Fahrenheit depending on the one you are comfortable using.

You can count on this device for accurate temperature readings. It provides you with temperature readings within 0.1 degrees. The temperature range for the thermometer is -50 degree Celsius and + 70 degrees Celsius. The operating temperature is -10 degree Celsius and + 50 degrees Celsius.

For the best results, submerge the probe into the fish tank to measure the temperature of the water. You do not have to submerge the thermometer, just the probe. The device is not too big, and it has a compact design that allows for discreet use. Applying the suction cup is also easy to keep it in place.


  • It has a compact design
  • Easy to use suction cups
  • The LCD display is easy to read
  • Provides accurate temperature readings
  • You can read the temperature in Fahrenheit or Celsius
  • The thermometer is easy to operate


  • It is accurate but very slow

Do you want a thermometer for your fish tank? The Aquarium Thermometer, RISEPRO Digital Water Thermometer is a perfect choice for you. When it comes to the performance and ease of use, the thermometer beats other models on the market.

You can quickly set it up in a few minutes by simply mounting the display unit in the fish tank and then place the sensor probe in the water. The two parts feature suction cups that provide an easy mounting.

This is a versatile thermometer that works well with different types of fish tanks as well as water. It doesn't matter if you are using salty water, tap water, marine water or fresh water in your aquarium, the device will work well and provide you with the accurate water temperature reading.

The thermometer provides a wide range, and it is accurate. It measures from -58 to 158 degrees Fahrenheit with an accuracy of +/- 1 degree Celsius. You can choose to use Celsius or Fahrenheit temperature units.

If you also have reptiles such as turtles and lizards, this thermometer will work well in monitoring their living temperature.


  • Suits different aquariums and water tanks
  • Perfect for reptiles
  • It offers accurate temperature reading in Celsius or Fahrenheit
  • It provides a wide range of temperature
  • It is easy to set up
  • It features a compact design
  • Features an easy to read LCD display with a remote submersible sensor probe


  • It falls easily in the aquarium

When you are buying an aquarium thermometer, you should be concerned with a device that provides accuracy when reading the temperature. One amazing thermometer that cannot let you down when it comes to accuracy is the American Thermal Instruments Aquarium Thermometer.

This is a pocket-friendly thermometer for aquariums that utilizes sensitive color changing liquid crystals. Reading the temperature is very easy because it is well calibrated.

The thermometer works well and responds immediately to the temperature when adhered to the aquarium. You can choose to locate it below the waterline or on the outside of the aquarium. You need to place the thermometer on the aquarium and press it firmly to keep it in place.

As compared to other LED thermometers, this one is easy to read. It is made with large numbers that make reading easy. The thermometer is also designed with each temperature indicator in a separate formulation made under strict lab specifications.


  • It sticks properly
  • Provides accurate reading
  • Very easy to read
  • Comes at an affordable price
  • It has sensitive color changing crystals


  • Not exactly accurate because it measures the temperature of the glass

This is another unique thermometer that you can choose for your aquarium. The thermometer is very easy to use and provides wide temperature range. For those who love compact units, this one will best suit you. It has a compact design, so it doesn't take up much space.

The thermometer features a quality LCD display that helps you get temperature readings with ease.

The device is made with a top quality suction base that ensures it doesn't fall off inside the fish tank and end up breaking. Another great thing about this thermometer is that it provides a wide temperature range. It has a working range of between -50 and +70 degrees Celsius. 

It has a long sensor cable, so you do not need to have the device directly beside the fish tank. It comes with an included battery, but it also works when plugged. For accuracy, you can entirely depend on this unit for accurate results.


  • Has a compact design
  • As easy to read LCD screen
  • Features a high-quality suction base
  • Wide temperature range
  • Small and lightweight
  • Doesn't require to be submerged in water


  • Complaints on quality

Different types of fish require different temperature levels. The type of fish that you have in your aquarium will dictate the optimal temperature that keeps them comfortable.

Ideally, most fish will be happy and comfortable in temperature that ranges below 76 degrees and 80 degrees F., but this temperature can vary based on the fish species that you have in your aquarium.

Owning an aquarium thermometer is great to ensure the fish stay in the right environment that is safe. For those who wouldn't want to spend much purchasing an aquarium thermometer, you can get the Fluval Nano Thermometer which is one of the affordable models available.

This is a slim and compact glass thermometer that is highly accurate. It provides a temperature range of 35-125 degrees F and providing you the aquarium temperature in a short time.

It has well-marked temperature markings which make it easy to read without straining your eyes. This thermometer is also designed with suction cups that provide a simple and reliable installation.


  • Comes at an affordable price
  • The temperature reading provided is accurate
  • It is well marked for easy reading
  • Suction cups provide an easy installation
  • It is a perfect size for your aquarium
  • A wide temperature range of 35-125 degrees F


  • Customers complain that the thermometer is too small to read

The next aquarium thermometer that you can choose for your fish tank is the Leegoal Digital Aquarium Terrarium Fish Tank Thermometer. This is a nice digital thermometer designed with an external thermistor with three feet insulated wire.

The thermometer has a simple user interface, so you will not have problems using it even if you have never used one before. It is designed with an easy to read LCD display that allows you to read temperature without struggle.

It features a suction cup so you can place it on any smooth surface. All you need to do is to submerge the thermistor inside the fish tank, refrigerator or any other place where you want to monitor the temperature. You can use the included flip switch from Celsius to Fahrenheit, and this helps in saving battery power.


  • It is easy to use
  • The LCD display is easy to read
  • Features a compact design
  • Offers accurate readings
  • Has suction cups for easy placing


  • Poorly made

Looking for a reliable and high-quality floating thermometer? Then you should try the Marina Floating Thermometer with Suction Cup. The thermometer is affordable and provides you with the accurate temperature reading.

It is easy to use the thermometer as well as read in both Celsius and Fahrenheit. 

It is made to float in a vertical position, and it has a suction up for those who would like to attach it to the walls of the aquarium. This thermometer doesn't have a probe or LCD display. It uses time-tested method with the use of mercury to measure that temperature. 

This makes it one of the most accurate thermometers that don't go off point. The thermometer also features safety zone indicators that help you know when the water is too cold or too hot for the fish.


  • Designed with a safety zone indicator
  • It has suction cups
  • Provides very accurate readings
  • It is easy to read and use
  • Doesn't need batteries to operate
  • Offers you with the convenience of reading temperature in Celsius and Fahrenheit


  • The suction cups leave marks inside the fish tank

How to Choose the Best Aquarium Thermometer

Choosing the best aquarium thermometers can be tricky especially if you are not familiar with aquarium accessories. Before you begin making your purchase, ensure that you know the following;

Thermometer Types

Aquarium thermometers are available in different types. You need to know the types that are available so that you can choose the best for your aquarium temperature adjustment needs. The most common types of aquarium thermometers include.

Stick on LCD thermometers-These are common thermometers in freshwater aquariums.

Floating/standing thermometers-They are put inside the aquarium, and they provide a direct measurement of water temperature.

Digital thermometers-The thermometers have a probe that is placed in the tank either temporarily or permanently. They operate on batteries, but there are others that can be plugged into the wall.

Ease Of Operation

Once you have determined which is the right type of thermometer that you want, the next thing is to check whether it is easy to use. Of course, you do not want to own a thermometer that is complicated to operate. Choose one that provides you with an easy time when you are using it.


Is the thermometer long lasting? You want to own a durable aquarium thermometer to serve you for many years. Before you purchase, you can read reviews online to find some of the most durable thermometers on the market with high ratings and positive customer reviews.


Does the thermometer provide you with accurate reading? You will be wasting your precious money purchasing a thermometer that doesn't provide you with accurate results. After all, the whole point of purchasing the thermometer is to help you the right temperature. Always check it provides accurate results because if the thermometer gives wrong temperature readings, this might end up affecting your fish.


When you are buying an aquarium thermometer, it should offer the performance you need in all types of tanks. Even if you buy one for a small tank, it should also offer the best performance in other types of tanks.

Final Words

Every aquarium owner should look forward to owning an aquarium thermometer to ensure that the temperature in the tank is at its best. I would recommend the above options that I have reviewed which have been tested for durability and accuracy among other features. They provide very accurate temperature readings which is very important for the fish and the plants in your aquarium.

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David Valle

I started this blog to provide advanced material, guiding you towards a better and more comfortable fishing experience. I deliver more than fishing gear guides, and motivate people to hit the water!