10 Best Aquarium Thermometer – How to choose the correct temperature?

Do you know fish and other aquatic creatures are sensitive to temperature just like humans? Well, these creatures behave differently when the water temperature changes even a bit. When deciding to buy an aquarium, you need to carefully decide whether your aquatic creatures can live conveniently inside the existing water temperature.

The question here arises is – how to know your aquarium water has the correct temperature?

There are aquarium thermometers designed to get an accurate reading of the temperature inside your aquarium. With its use, you will be able to easily check whether the inside water has a suitable temperature for your fish and other aquatic creatures or not. Take a look at the 10 best aquarium thermometers described below

Top 10 Best Aquarium Thermometers

Image Product Name Feature Price
Editor’s Choice

Marina Floating Thermometer with Suction Cup Temperature Accuracy: +/- 1 ° C

Temperature range:  70°C to 80°C

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HDE Digital Aquarium Thermometer with Thermostat Water Temperature Control Temperature Accuracy: +/- 0.1 ° C

Temperature range:  -50° C to +70° C

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Zacro LCD Digital Aquarium Thermometer Temperature Accuracy: +/- 1 ° C

Temperature range:  -50° C to +70° C

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Leegoal Digital Aquarium Terrarium Fish Tank Thermometer Temperature Accuracy: +/-1 ° C or F

Temperature range:  -50° C to +70° C

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JW Pet Company Smarttemp Thermometer Aquarium Accessory Temperature Accuracy: +/-1.5 ° C or F

Temperature range:  78 degrees F to 88 degrees F (green zone)

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American Thermal Horizontal Aquarium Thermometer Temperature Accuracy: +/- 1 ° C

Temperature range:  66 to 84 degrees

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Zoo Med Digital Thermometer Temperature Accuracy: +/- 1 ° C

Temperature range:  10 F to 140F

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Digital Touch Screen Fish Tank Thermometer Temperature Accuracy: +/- 0.1 ° C

Temperature range:  0°C to 70°C

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Keynice Digital Thermometer, High Accurate-Black Temperature Accuracy: +/-1℃

Temperature range:  -58F to +230F

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LCR Hallcrest A-1005 Liquid Crystal Vertical Aquarium Thermometer Temperature Accuracy: +/-1℃

Temperature range:  19°C to 29°C

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Marina Floating Thermometer with Suction Cup

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What if I tell you that you can precisely measure the aquatic temperature to let your fish stay quite comfortable? You will admire the accurate readings taken by this Marina floating thermometer. It is quite easy to read the output readings. One of the best features of this Marina aquatic thermometers is it comes with suction cups. They will allow the thermometer to stay stuck on the walls of your aquarium. So, there will be no fall issues.

Now you need not worry about whether your aquarium is at an appropriate temperature or not. Simply use this device to get accurate temperature readings. Do you know how this Marina thermometer works?  Well, it is uniquely designed to float in vertical alignment in water.

You may wonder what the most beneficial aspect of this product is? This indicator will present safe temperature readings for tropical fish. Also, it is suitable for fresh or saltwater aquariums. With the height being 4.25 inches, you will not find any hassles while setting it up inside the water. For the convenience of users, this thermometer is made to provide readings in Fahrenheit and Centigrade.


  • Provides extremely accurate readings
  • The output is quite simple to read


  • Occasionally the suction cup produce chemical odor
  • Comes with low durability

HDE Digital Aquarium Thermometer with Thermostat Water Temperature Control

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HDE introduced this digitally operated aquarium thermometer to make sure your tiny creatures in water always stay comfortable. Basically, this fish tank thermometer is quite simple to use and it will firmly stick to your aquarium’s glass. As a result, you will get precise temperature readings whenever you want. Based on your needs, you can measure temperature in °C or F. With its wide temperature range and accuracy within 0.1 degrees, I was benefitted a lot. This is because this measurement accuracy and wide temperature range present a quite comfortable environment for the creatures inside.

Do you know what is inside the structure of this digital aquatic thermometer? Well, it includes two main components i.e. the display and the sensor. Each end possesses a suction cup connected to it. This cup will firmly attach to your aquarium unit. While using it, we have to make sure we only dip the sensor end inside the water. What I liked the most about this digitally operated thermometer is it is made water-resistant. But it is important to know that the unit will not work after being fully submerged in the water.

After I have set it up, I simply pressed the ‘On’ button and then I was able to take measurements conveniently. This simplicity of use has surprised me and will benefit the customers as well. In order to shut off this thermometer, I just pressed and hold the included ‘On’ button till the display becomes dark.


  • Equipped with long-lasting battery life
  • Made water-resistant


  • When battery status is low, it sometimes displays incorrect temperature

Zacro LCD Digital Aquarium Thermometer

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The digital type aquarium thermometer from Zacro shows an easy-to-read digital display. The temperature readings can either be taken in Celsius or Fahrenheit based on your choice. When I used it, I was able to take readings as precise as up to 1 degree. This indicates how accurate it is to use this digital thermometer for the aquarium. When I looked at the detailed specifications of this unit, I found out that it comes with an LR44 battery. You just need to open the battery cover and then put the battery inside with positive side facing upwards. Now the LCD will show the room temperature.

I was surprised by the easy operation –I simply attached the display unit towards the exterior of my tank with the help of the suction cups. After that, I submerged the probe inside the tank water, and that’s it! To turn it on, you simply need to press and hold its power (PWR) button. To turn it off, make sure to hold the power button for duration of 3 seconds.  What I liked the most about this device is its LCD display is bright and displays accurate readings whenever used.

Compared to a glass thermometer, the accuracy of this digital thermometer is far better. The output is always simple to read and also considers decimals. One of the best features I liked is it does not emit unpleasant odor chemicals or presence of rubber on the parts. Also, it will be quite simple to move and located it anywhere. Being user friendly, you will find convenience while measuring the temperature. The suction cup gets perfectly attached to the front glass or at any place you want on the body of this thermometer.  You simply need to drop in the probe and then attach the probe to the glass.


  • Presents high temperature accuracy
  • Quite easy to hook up


  • May not last longer

Leegoal Digital Aquarium Terrarium Fish Tank Thermometer

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For different types of aquatic creatures inside your tank, this thermometer will let you present a comfortable environment. This is because it shows the precise temperature, based on which you can make the required changes. While using it, what I found is that this digital thermometer contains an external thermistor along with 3 feet insulated wire.

What I liked the most is that this terrarium fish thermometer is made in compact design. This design appears beautiful in any aquarium tank. With the inclusion of the suction cup, you will be able to place it to any smooth surface. Another benefit that I liked is it will save battery power by the use of on/off button. You simply need to flip to switch amongst the Celsius and Fahrenheit.

In your tank, simply dip the probe inside. Its operation is made digital so if you are attempting to make water change, this device is the best. When you want to observe the temperature of the inside water, simply stick this thermometer in your water tank. Since it is small in size, I was benefitted a lot with space-saving features. When we need to save the battery, we can power it off and then turn it on immediately when required to measure water temperature. One more thing I liked is its probe is made waterproof, so it can be immersed in water. Also, you can read the temperature of open air.


  • Comes in a tiny size
  • Provides comfort to the creatures inside


  • Sometimes, it does not show the exact temperature
  • Affordably priced

JW Pet Company Smarttemp Thermometer Aquarium Accessory

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What we need to notice unique in this thermometer from the JW pet company is it comes with a magnet. This model of the smart temperature thermometer enters deep inside your tank while the magnet reaches outside. In this way, the product will be held firmly in a fixed place; there is no need to use suction cups. What I liked the greatest about this smarttemp thermometer is it presents a green safe zone. This zone will denote the most favorable temperature range. With excellent temperature accuracy, you will not find errors while measuring the inside temperature. There are large numbers shown on the screen which are easy to read.

Looking at the dimensions, it is approximately 6 inches long and about an inch wide. I admire the white color in the background. It lets it easy to read the black numbers in the temperature readings. While cleaning the body of aquarium i.e. the aquarium glass, the magnet enables you to conveniently move it around.  This too maintains contact amid the two pieces.


  • Shows readings in large-sized numbers
  • Convenient to install and simple to read


  • Comes with the poor build quality

American Thermal Horizontal Aquarium Thermometer

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This horizontal thermometer for aquarium provided me with reliable, steady readings. These readings gave me sufficient confidence to determine the water temperature inside the tank. I am pleased to know that now my fish need not swim around the wires. Also, I am confident that they get a favorable condition to swim freely inside. The working operation makes the process of reading simple. It can be removed if you want to reposition it. Though I moved it around many times, it still attaches well.

The aspect that I liked the most is it allows me to clearly observe the temperature. There are few aquarium thermometer models that do not show the temperature readings brightly. But this one just seemed perfect to me.

After regularly using this product for my aquarium tank, I found my fishes moving more freely than ever. Also, they are able to swim around with high effectiveness and pleasure. I am easily able to find out if the water temperature gets too cold or too hot. All I need to do is mount it on the outside of my aquarium.

What attracted my attention is the temperature readings are clearly shown in a bright display. So, I never need to make any guesses. I have used this product to substitute thermometers with long wires entering inside the tank. One more thing that grabbed my attention is it comes with the different colors of the crystals. They are simple to understand. There will be no issues while mounting it horizontally or vertically; mounting in any fashion will present accurate temperature. One of the bonus points of using this product is you will be able to rearrange as required. The compact size and accurate readings are the key benefits.


  • Accurately reads temperature to 1 degree
  • Simple to use and remove


  • Its readings are too dark to read if you do not use flashlight.

Zoo Med Digital Thermometer

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All digital thermometers for aquarium do not come with a remote sensor probe. But this Zoo Med thermometer includes it. So, I am able to measure the temperature readings precisely. This digitally operated terrarium thermometer comes digital readout to indicate the temperature in Celsius or Fahrenheit.  Though there is no lighting available on the display, I found it quite simple to read. We are satisfied with the fact that the pack comes with all necessary parts like suction cup, battery, etc. What I liked the most is that the large numbers precisely denote the temperature readings. These readings will be easy for you to read during any time of day.

I liked its crisp display and its good contrast. There will be no troubles while switching it between Celsius and Fahrenheit. When you use it, you will notice that the suction cup sticks perfectly to the side of the plastic body. One more benefit of using this digital thermometer is its cord between the sensor and display is sufficiently large. So, it makes sure the set up is easy. The LCD display makes the process of reading the output easy. Since the numbers in the display are large, they are simple to read during any time of day. You can read the output even with the room light turned on.

It is always the best idea to keep your tiny aquatic t creatures at the appropriate temperature and without disturbance. The same is exactly achieved by this digital thermometer unit.  I liked the fact that the original batteries still work for me and haven’t created any issues.


  • The built-in batteries last longer
  • Its display is not extremely bright, so the readings can be seen in the dark


  • Included suction cups only adhere to glass, they don’t work with any surface
  • Sometimes, it will randomly turn on by its own, so it increases power consumption

8. Digital Touch Screen Fish Tank Thermometer

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What if I tell you that an aquarium thermometer comes with high efficiency and beautiful appearance too? You may be surprised but with this digital touch screen based fish tank thermometer, you will be benefitted from these aspects. Actually, it is prepared in a compact size and shows modern appearance. I liked the easy-to-read LCD screen to show precise temperature readings. With its use, I was able to keep my pet fish healthy, active and happy.

We all dislike the messy wires in water and this hassle will be removed by this thermometer. This is because it does not come with any probes or untidy wires. The rear temperature sensor adheres to the exterior of the tank. This will avoid water infiltration concerns and electronic oxidation. What I liked the greatest is it has a huge crystal touch screen. This smooth screen makes it simple to read the temperature even from a far distance.

It is extremely simple to operate –I just pull down the battery cover beneath the screen, put in the battery, shut it off, and stick on. As a result, I was able to easily read the temperature of the water in my tank. It will be easy to switch to °C / °F by just pressing the switch up or down.

The reason why this fish tank thermometer is termed versatile is it is widely suitable for different types of water. For example, you can use it for tap water, freshwater, marine water, salty water, etc. There will be no inefficiency while measuring the living temperature for reptiles. The reptiles like turtle and lizard will get appropriate temperature to live inside. With the help of a precise temperature sensor sticking on the tank’s surface this product will present accurate readings. I found these readings in broad temperature range and with outstanding accuracy.


  • Simple to install
  • Shows attractive design


  • Does not compatible with acrylic tanks
  • Not waterproof
  • Does not come with a probe to place inside your tank

Keynice Digital Thermometer, High Accurate-Black

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A smart working digital thermometer from Keynice, this product is made in attractive black design. It is quite easy to use and portable. There is a beautiful color screen and the responsiveness is excellent. You may find this accurate thermometer widely used for checking the temperature in your aquariums, cars, HVAC air ducts, pet habitats, computer towers, etc.  You may also use it to read temperature inside or exterior your house, test appliance, pools, farms, etc.

The accuracy of 1degree Celsius denotes that this digital thermometer can sense warmness or coldness even by a change of 1 degree. I liked how its designing is done in flush-mounted; also, you can mount it on the surface. When mounted in any of these ways, there is a professional look conveyed. The reason why it is popular is it has a unique digital temperature meter. Also, there is a 3.3 feet long cable as well as a remote temp sensor probe.

One more thing I liked about this black aquarium thermometer is it has Fahrenheit to Celsius selector switch. This switch is present on the rear part of unit.  The capability to automatically update the temperature reading after every 2.5 seconds is one more benefit of this product.


  • This temperature sensor probe is resistant to corrosion
  • Not expensively priced
  • It is USB powered, so no need to replace batteries


  • The temperature begins to vary by a few degrees

10. LCR Hallcrest A-1005 Liquid Crystal Vertical Aquarium Thermometer

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Are you in need of reading water temperature precisely from a bit far distance? If yes then this vertical aquarium thermometer is the best option. I was amazed to see how the temperature illuminates up brilliantly. I did not find any trouble while sticking it to the glass. Immediately after placing it on the glass, it will illuminate up and sense the temperature. In terms of readability, this product is simply the best.

Till now, I have purchased and tried few thermometers but this one is certainly the best. There are tons of features installed inside to simplify the process to read the temperature.  The other thermometers are not as sensitive as this one. The moment I place it on the glass tank, I am able to get a precise reading.

What I liked is its unique design that firmly sticks to the exterior of your tank. Once set up properly, it will provide you a range for the measurement of water temperature. The best way of setup is attaching it to the side of your tank, i.e. at the farthest distance from the heater. In this way, it will not obstruct the view into the tank and offers a precise outcome. The


  • Can be easily installed vertically
  • Provides bright illumination for temperature reading


  • With your tank light on, it will not show numbers

Buying Guide For Aquarium Thermometer

Every aquarium thermometers differ from one another based on temperature measuring accuracy, temperature range, and a few more aspects. We all agree with fact, don’t we? If your need is focused on high precision temperature measurement for your fish tank, you need to carefully assess the buying guide.

The buying guide for aquarium thermometer will highlight the associated factors to take into account. We cannot check each and every model of such thermometers to know the accuracy of each of them. Therefore, it is important for us to look at the factors that make the buying process simple. Take a look at the below-discussed buying guide for aquarium thermometer.

Accuracy of Measurement

The flawless working of our aquarium thermometer relies on how accurately it measures the temperature. When we get inaccurate measurement, it may lead to the demise of creatures inside. There are many aquarium thermometer models that show up to the degree of accuracy at which they will record temperatures.

When we choose a decent quality aquarium thermometer, it will come with accuracy within +/-2°F. The thermometers presenting reduced accuracy are not at all recommended for the growth and life of fish. We may find few models on the market that are less accurate than what they claim to be.

Therefore, it is the best idea to get an appropriately calibrated digital thermometer. By this, we are allowed with accurate measurement of the temperature of our water tank.

Range of Temperature

We need to choose a temperature that presents the readings in a range varying from 50 to 104 degrees Fahrenheit. This range is a perfect one and we will not find any harm to the aquatic creatures inside when there is this range. The wide range of temperature is usually the best to consider if we want to get effective temperature measurement outcomes.

Ease of Installation

Have you ever thought what would happen if the aquarium thermometer is inappropriately setup? It is significant to check the setup and installation procedure of aquarium thermometer before making a purchase. We find most of these thermometers are quite easy to use. Also, we need to make sure they do not demand much time for installation.


The best quality aquarium thermometer is the one that comes with resilient build quality and capable to last longer. We may have not to pay higher for a durable quality aquarium thermometer, isn’t it? but it will definitely last longer.

If you purchase a poor quality aquarium thermometer that boasts low durability then the inside liquid may break off and spill on the creatures inside. This may result in their death. So, we are always recommended to focus on how resilient your aquarium thermometer is.

Ease of Reading The Outcomes

Everyone likes to view display clearly with large numbers, isn’t it? Those thermometer models with huge-sized LCD displays are quite simple to read. This will benefit us the most if anyone of us are facing eyesight problems. From a bit far distance, it can be difficult to observe the precise reading on these thermometers. It is known that the adhesive strip models usually make use of a system of different colors. They will easily denote the precise temperature. Hence, we need to read the instructions to find out what each color denotes.

Power for Operation

We all know that operation of digital aquarium thermometers need batteries. When using such types of thermometers, you may face hassles when the battery dies and there is no replacement option available. On the other hand, we found that the adhesive strip and liquid-filled thermometers do not require batteries for their operation. So, they are better to keep as a backup even though you have a habit of using a digital model.


Have you ever thought your chosen aquarium thermometers could work in different environments or not? If not then you have to check whether your thermometer is designed to function outside the aquarium or not. In many situations, you may need to use it for other applications other than aquatic needs. For example, we may need it to measure the room temperature, cars’ temperature, etc. demands versatility. So, if our chosen model is versatile, it can work excellently for different applications.


Based on the reviews, we found that most of the aquarium thermometers do not need much maintenance. All you need to do is change the battery in its body from time to time. Do we like to change the battery frequently? Definitely not! When we buy a cheap quality aquarium thermometer, we may end up changing it frequently and receive inaccurate results.

Liquid leakage

The leakage of mercury or alcohol or the liquid contained inside your aquarium thermometer creates a lot of damabe. If it does, it will harm the aquatic creatures and may lead to their death. Buying a decent quality thermometer will make sure the contained liquid will not shatter off. If the liquid leakage occurs, the chemicals could prove toxic to the fish. Therefore, we need to go for a 100% water change. The best idea we can follow is removing every glass or weighted ball out of our fish tank if the thermometer shatter. If our thermometer includes mercury inside, we have to be careful because mercury is risky for human beings also.


The appropriate placement of your aquarium thermometer is above the gravel line. In this way, we will get a precise reading of the water. Generally, the standing and floating thermometers enter inside the aquarium on the reverse side of the heater. If we position thermometer near the heater, it may read higher than the real temperature. This will assist us to check whether the water temperature is the same all through the aquarium. Such types of thermometers would incorporate a suction cup to grasp the thermometer to the glass.

There are certain floating thermometers that stir around on the topmost part of the water. We can position it in the best way by placing it halfway up the glass. In this way, it will be directly in our line of sight. We always like simple to read thermometer but not obstruct the vision of the fish.

Frequently Asked Questions – FAQs

What is the finest temperature for a tropical aquarium?​

The best temperature at which your fish feels happy, independent inside and grow well under your aquarium is important to know. The majority of the aquarium fish prefer the temperature range from 22 to 26 °C (71.6 -78.8 °F).

Where to put the thermometer in your fish tank?

If you are deciding to attach a stick-on thermometer over the exterior of your tank, be sure to place it beneath the waterline. Also, make sure it is away from heaters, vents, and sunlight. For a floating type thermometer, you have to attach it through a suction cup towards the interior of the tank.

How you can read an aquarium thermometer sticker?

Firstly, wipe the exterior of your aquarium using a glass-cleaner and then pat it dry with a towel.  Now take out the plastic from the strip. After that, put the strip free of strikes on the tank exterior. Allow it for 30 minutes, and then check the color of strip. It will help you monitor the precision of the temperature.

Do aquarium thermometers need batteries for operation?

The majority of the aquarium thermometers incorporate a minimum one battery in their structure.  If needed, you can purchase extras. You can check the package details to know which battery it makes use of.

What is the life expectancy of an aquatic thermometer?

The life expectancy of an aquatic thermometer differs based on its type, manufacturer, and materials used in the making. For example, an alcohol made thermometer will have a different life expectancy than a mercury one. Typically, life expectancy is at least 10 years.


Knowing the exact temperature at which your fish and other aquatic creatures feel comfortable inside is important. Choosing any of these aquarium thermometers will let you precisely check the water temperature and maintain its appropriate level.