The Best Aquarium Thermometer: Reviews & Guide 2022

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Best Aquarium Thermometer

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Keeping the fishes alive requires using the right equipment to provide the proper condition they looked-for. One thing to consider is the water temperature which must neither be too hot nor too cold. This can have negative effects on the aqua-creatures if not properly monitored. That is why the best aquarium thermometer is necessary to have a stable temperature for your fish. It measures the water temperature in the fish tank depending on the need of the fish species.

To help you out, we’ve mentioned a buying guide and 12 reviews of the best products with pros and cons.

Important Factors to Consider

Aquarium thermometers aren’t that expensive yet it doesn’t mean you need to compromise the quality. Here are the main factors to be considered in picking the best aquarium thermometer for your aquarium:

Types of Aquarium Thermometers

It includes Stick-On, Standing or Floating, and Digital Thermometers. It is arranged in an ascending price range and quality. Choose what suits your need and your fishes need.

The table below shows a summary of the pros and cons.

Types of Aquarium Thermometers PROSCONS
Stick-On Aquarium Thermometer Easy to read



Not prone to breaking

Inaccurate reading


No alarm feature

Standing or Floating Aquarium ThermometerVery accurate


Doesn’t require batteries

Fully submerged in the water

Not readable


Prone to breaking

No alarm feature

Digital Aquarium ThermometerHas temperature probe


Highly accurate

Has alarm feature



Requires batteries and power

Easy to Install

It can be installed either outside of the tank or by submerging it into the water. Avoid a model that is complicated to setup.

Accuracy and Range

The accuracy level must be +/-1 degree F to keep the fishes out from distress. The accurate range of temperature readings is from 50 to 104-degrees F. If these two are accurate, the fishes will be well-off.


This feature is more applicable to the aquarium thermometers that are submerged in the water. It must be made from durable materials except for glasses that aren’t prone to breaking. Remaining accurate over time is a good sign for a good buy device.


It is important to have a readable thermometer for aquariums to properly monitor the current temperature status. A clear display is what you need to look for.

How to Read an Aquarium Thermometer?

It shows three different colors. One is for correct temperature while the others are for cooler and hotter temperature. It would be difficult for first-time users to determine the accurate reading.

There are three stages on how to read an aquarium thermometer, including:

#1 Wipe the aquarium’s exterior with glass-cleaner and dry with a towel. Avoid using chemicals for it may contaminate the water.

#2 Remove the plastic off the strip. Then, place the strip free of bumps on the tank exterior.

#3 After 30-minutes, check the strip’s colors to monitor the accuracy of the temperature. In this process, you’ll see the difference between each color.

Top 12 Aquarium Thermometer

The most-rated, most-reviewed, and well-recommended products came from Amazon. Each aquarium thermometer may depend on the kind of aquarium you’re using.

Keynice Digital Thermometer

It is under the digital-type of thermometer which is affordable as compared to other models. The probe is rustproof stainless steel. It gives a good degree of accuracy in measuring temperature. It can only be submerged in the tank for it doesn’t include suction cup. It’s through a USB port that it starts working.

You can visibly read the results on the outside of the tank through its large digital display. It measures temperature ranges from -58 to +230 F with +/-1 degrees F accuracy level. You can change the temperature measurement from ̊C to ̊F or vice versa on the back of the unit.

Its positioning can only be flush-mounted or surface-mounted.


  • Accurate and reliable digital thermometer
  • No use of batteries
  • Rustproof probe construction
  • Auto-updates every 2.5 seconds


  • Requires the use of USB adaptor
  • No alarm system
  • Cannot be mounted to your tank

HDE Digital Aquarium Thermometer

HDE brand is almost the same as Zacro and RISEPRO brands in looks and in functionality. Then again, it is a digital aquarium thermometer that is within your budget but now comes with a suction cup. It can either be placed underwater or mounted outside the tank, whichever is more preferable. It works through the included single button cell battery or through a spare.

HDE Digital displays the results on the large LCD screen which is very readable. It’ll give you an accurate reading over time. It offers a wide range of temperature from -58 to 158-degrees F with the accuracy of +/- 1-degree F. The installation process is easy to follow in just a few minutes.

This thermometer is great for both saltwater and freshwater marine life. It is cheaper than the other models so don’t expect for perfection.


  • Clear display
  • Quick to setup


  • No temperature alarm

Marina Deluxe Floating Thermometer

Let’s try the other type of aquarium thermometer which is the floating thermometer. This type will surely fit your bill and it is highly recommended. The downfall of this device is it is technically breakable because of the used glass material. On the other side, it gives accurate readings due to its installation location. You can let the device float in the water by using the suction cup to keep it in place.

You can read the temperature level through the liquid inside just like a traditional mercury thermometer. Don’t worry as the liquid isn’t out of mercury and so safe for the fishes. Between 30 to 120-degrees F is the temperature range. There’s a safety zone indicator for people with poor eyesight to easily read the markings.


  • Very affordable
  • Provides accurate readings
  • Doesn’t require a power source


  • Uneasy to read the markings for people with poor eyesight
  • Flimsy suction cup

SunGrow Digital Betta Thermometer

It is suitable for all types of aquarium, especially for a betta tank. SunGrow Digital Betta Thermometer might be the best alternative for floating thermometer because of its price. It costs a bit higher than the prior and offers a different set of unique features. You can read the markings in either ̊F or ̊C by pressing the power button for 3-5 seconds.

The company uses up durable plastic material in making the device. It ensures proper water temperature without being affected by the room temperature changes. The temperature’s range is -58 to 158-degree F at optimal accuracy level. It operates with the use of the included 1.5volts battery.

It comes with two suction cups for easy setup. The screen reader shows a visible reading of markings.


  • Very much accurate
  • Cannot be altered by the room temperature
  • Durably made


  • Bad reports on the device
  • Issues on its quality

Zoo Med Digital Thermometer

Zoo Med brand is very popular to most aquarium owners. It got the most numbered customers reviews and the majority of it is on the positive side. One of the most admired features on this thermometer is its immersing external sensor. Unlike the other aquarium thermometers, it still gives accurate readings with that setup. Both ̊C and ̊F measurement is shown on its LCD readout.

It includes a remote sensor probe to easily read the temperature status anytime. The external sensor will never be ripped off when submerging into the water. And, that’s a good thing for a longer time of use for your growing fishes.


  • A very visible LCD readout
  • Within your prepared budget
  • Unique installation setup


  • Complaints of missing battery when delivered
  • The unit doesn’t last long

Lifegard Aquatics Digital Temp Alert

Reading the temperature level from a distance is easier with this 4″ by 4″ Lifegard Aquatics Digital Temp Alert. With its huge monitor, even the oldies can clearly see the temperature status. Moreover, the unit shows both room and water temperature with the help of an internal thermometer and probe, respectively. You can freely place the device on either freshwater or saltwater-containing aquarium.

It is by the included 3A battery for the unit to start working. The unit works by attaching it to the aquarium glass with the use of a suction cup or by standing alone. Further, there’s a built-in programmable alarm that signals everyone whenever the temperature is too low or too high. It doesn’t just save you from further expenses but also concerns more on the wellbeing of the fishes.


  • LED light indicators
  • Wide range of temperature measurement
  • Easy to monitor


  • Expensive

LCR Hallcrest A-1005 Aquarium Thermometer

Try out the LCR Hallcrest A-1005 Aquarium Thermometer that doesn’t submerge. You don’t need to submerge the unit to have accurate readings. It’ll give you the best measurements by sticking the device outside the tank. This allows movable setup as you can move it from place to place. Plus, the price is affordable.

The temperature status is very readable because of how it is set up. It is mounted outside the tank in a vertical position for easy temperature reading.

Most users consider the unit as a movable thermometer. Just don’t ever try to submerge the device to lengthen its useful life. Some users said that it stops working after a few months of operation.


  • Movable around the outside parts of the tank
  • Easy to set up
  • Low-cost device


  • Reports on inaccurate readings
  • Short-lived device

SUKRAGRAHA Traditional Stick-on Thermometer

Stick-on is another type of aquarium thermometer that costs lesser. It is the easiest to install thermometer by its direct peel-and-stick configuration. The simpler it needs to be installed, the fewer disturbances it’ll cause on the pets. The delivery includes 10-pieces of the stick-on device with adhesive back. Simply attach one strip on the aquarium’s exterior surface.

It measures a bit lower temp range from 64 to 93-degree F yet provides better accuracy. With the help of bright light, reading the markings would be at ease. Even without evident light, you can still visibly read the labels. It shows unlike temperature levels in altered colors for you to easily distinguish which is which.

Cleaning the stick-on thermometer doesn’t steal more time for it’ll eventually get wet and dry.


  • Inexpensive
  • Clear temperature range display
  • Enhanced accuracy


  • Must not be exposed to water

American Thermal Horizontal Aquarium Thermometer

As compared to LCR Hallcrest A-1005, you can mount the device in a flat position. The unit is movable on the outside of the tank. An exact temperature sense is likely with this great device. Press the thermometer solidly to keep it in place on either the load line or outer tank surface.

In other words, the device is a stick-on type as agreeing to how it is installed. The construction is very light and compact. It has sensitive color-changing fluid crystals which are good for fishes. Anyone can easily see its enlarge accurate result figures. The device is under a strict laboratory specification about its temperature pointer.


  • Comes in a pack
  • Sensitive color-changing crystals
  • Mounts well on the tank


  • May adopt the glass temperature

JW Pet Company Smarttemp Thermometer Aquarium Accessory

Not a digital thermometer but just a simple one yet a reliable choice as an aquarium thermometer. This must be the most traditional-looking water thermometer as ever listed. With no use of suction cups, the Smarttemp Thermometer can stay in place through the help of magnetic substance. The product is from China but it can last for years.

The assembly is a combination of glass and plastic materials on the part of lodging and fins, respectively. Those are high-quality materials and so away from breaking and sinks very well. Expect for a low error margin which is presumably, + or -.2-degrees F. It has a green safe zone for optimal temperature range.


  • Easy to read
  • Kept in place
  • High accuracy level


  • The issue on its red-light indicator

Pet Magasin Digital Thermometer and Hygrometer

There are two vital tools in petting fishes. It includes thermometer and hygrometer. Happily, Pet Magasin offers both in one device only.

A hygrometer is apt for gaging air humidity. While the thermometer for water temperature. Cling the 2-in-1 device outside the tank but don’t immerse it. However, its tough external shell can withstand water sprinkles for a long time.

It provides both ̊F and ̊C readouts on the LCD display. Accurate readings for both temperature and humidity are accessible. Stains are nowhere to be found on your tank’s surfaces. It greatly works not only for aquariums but also for terrariums.


  • Waterproof
  • 2-in-1 device
  • Cost-friendly


  • Battery life issue

General Tools AQ150 Aquarium Thermometer

Setting desired temperature alert is possible. It is through the device’s built-in button. This makes the fishes happy and pleased with their place. It features a backlight display and foldaway stand for convenience. Additionally, the company includes a suction cup for at ease connection to the sensor. It is a CE approved product.

The temperature ranges from -58 to 158-degrees F. It is immune to corrosion which makes it last longer. Its jumbo-sized display enables the reader to monitor the temperature level at ease.

Its temperature alerts are what makes this unit ahead from its competitors.


  • Comes with many accessories
  • Has memory function
  • Alerts feature


  • Deteriorating accuracy


One way to lengthen the life of your fishes is by having one of the best aquarium thermometers on the market. It helps to sustain the water’s proper level of temperature. Of course, with the supervision of the owners.

Out of the 12 thermometer units above, which one will you choose?

Share with us in the comment section below!