Maintaining the internal environment of your aquarium is crucial for keeping healthy fish. If conditions change, your fish will fall ill and could die.
When designing your aquarium, you should have considered the ideal water temperature, since it is one of the important environmental factors.
You can buy a heater to warm up your water, but how can you be sure that it is at the temperature you want?
A thermometer is an easy way to check this. Place one at the opposite side of the tank to your heater to get an accurate reading of the tank’s temperature.
Thermometers come in all shapes and sizes, so it can be difficult to determine which will be best for you. Here we discuss 10 different thermometers, to help you decide.
Comparison Table
| PRODUCT | FEATURES | LATEST PRICE |
|---|---|---|
1. Marina Deluxe Floating Thermometer with Suction Cup  |
| Check Price |
2. TOOGOO Digital LCD Thermometer  |
| Check Price |
3. Inkbird Wireless Thermometer and Hygrometer  |
| Check Price |
4. American Thermal Horizontal Aquarium Thermometer  |
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5. Lifegard Aquatics Digital Temp Alert  |
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6. UPLY Digital Aquarium Thermometer  |
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7. AODE Digital LCD Aquarium Thermometer  |
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8. POPETPOP LCD Digital Aquarium Thermometer  |
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9. JCreate Aquarium Thermometer  |
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| 10. SUKRAGRAHA Traditional Stick-on Thermometer Strip |
| Check Price |
Our Best Aquarium Thermometer For 2020 Reviews and Comparisons
1. Marina Deluxe Floating Thermometer with Suction Cup
Product Highlights
This is a very simple analog thermometer that anyone can use. It attaches to the inside of the aquarium via suction cups.
Colors are used to indicate the safe temperature range for aquarium fish, but it measures far beyond this range. The thermometer is 4.3 inches tall.
Features
- Suction cups
- Safe temperature zone indicator
- Temperature range of 30°F to 120°F
What We Like About Marina Deluxe Floating Thermometer with Suction Cup
The design of this thermometer is simple which makes it very easy to use. It permanently sits on the inside of your aquarium, so you can check the temperature whenever you want.
This makes it great for beginner aquarists, and so does the price. If you have never kept fish before, you don’t want to spend lots of money on gadgets after buying an expensive tank and filter. This thermometer makes a good cheap option.
What We Don’t Like About Marina Deluxe Floating Thermometer with Suction Cup
To achieve the simplicity and price of this design, certain things had to be sacrificed. One of these is precision. Only whole numbers are shown, and you read the value of yourself, which can be subjective.
Reading the measurements can be difficult from certain angles or in low-light environments.
PROS
- Cheap
- Convenient to use
- Easy for beginners
- No batteries needed
CONS
- Lacks precision
- Can be difficult to read in certain environments
2. TOOGOO Digital LCD Thermometer
Product Highlights
The TOOGOO Digital LCD Thermometer comes as two components, an LCD digital display, and a sensory probe. The two are connected by a long cable and held in place by suction cups. Measurements are given to 0.1 degrees and you can choose between Celsius and Fahrenheit.
Features
- Digital LCD screen
- Measures Celsius and Fahrenheit
- Suction cups to hold components in place
- Precise to 0.1 degrees
What We Like About TOOGOO Digital LCD Thermometer
This cheap digital device measures temperature to 0.1 degrees, so you can monitor changes in temperature more closely. You can swap between Celsius and Fahrenheit, giving it a global appeal.
The display and sensory probe are connected by a long cable, so you are free to place them far apart if you need it. Both components have a suction cup for mounting.
The screen can be turned on and off which helps to save battery.
What We Don’t Like About TOOGOO Digital LCD Thermometer
Since it is cheap, it has limited features. One thing missing is a backlit screen. Without this, it is very difficult to read the temperature in darker rooms.
Your only option to power the device is with batteries, you cannot use a power outlet. This means you will have to keep replacing the batteries if they run out, but at least some are included with the product.
PROS
- Clear digital display
- Cheap for a digital device
- Long cord gives more mounting options
- Can turn the display on and off
- Small and light
CONS
- LCD screen is not backlit
- Must use batteries, not a power outlet
3. Inkbird Wireless Thermometer and Hygrometer
Product Highlights
This thermometer brings monitoring your aquarium into the 21st century. By use of a free mobile app, the device will send data to your phone via Bluetooth.
Internal and external probes let you monitor inside and outside of the tank. Temperature and humidity measurements are taken and can be stored for a short time.
Features
- Free IOS and Android app shows data remotely
- Internal and external probe
- Measures temperature and humidity
- Set a sampling interval and store data
What We Like About Inkbird Wireless Thermometer and Hygrometer
Your phone can attach to the device using Bluetooth. The free app makes accessing the data easy and clearly shows changes in temperature and humidity over time because it stores data for up to 20 days.
The internal and external probes let you study the conditions of your room and your aquarium. All measurements are accurate.
The device itself has long battery life.
What We Don’t Like About Inkbird Wireless Thermometer and Hygrometer
One of the best features of this thermometer is the fact that it stores data. However, it can only store so much. You must record the data elsewhere if you want to monitor temperature over long periods.
The circular case looks smart, but the cord reaching into the water can look untidy.
PROS
- You can store data to monitor changes
- The free app is accessible and easy to use
- Measures room temperature, room humidity, and water temperature
- Gives accurate measurements
- Long battery life
CONS
- No way of attaching external probe in the aquarium
- Lose data when the datalogger is full
4. American Thermal Horizontal Aquarium Thermometer
Product Highlights
This simple thermometer is a horizontal strip that sticks to the outside of your aquarium using adhesive liquid crystals. You can move it by gently peeling and placing it elsewhere. Colors and numbers indicate the temperature, which is easy to see at a glance.
Features
- Mounts on the outside of the aquarium
- Can be moved after attaching
- Clear display
What We Like About American Thermal Horizontal Aquarium Thermometer
This is another thermometer that is great for beginners because it is cheap and very easy to use. The temperature is clearly displayed due to the use of colors.
The measurement can be read from any angle, unlike suction cup thermometers.
The American Thermal Horizontal Aquarium Thermometer produces accurate readings compared to other similar thermometers. It can also be moved to different locations, whereas some can’t.
What We Don’t Like About American Thermal Horizontal Aquarium Thermometer
While this is a convenient thermometer, it doesn’t give the precision that digital alternatives offer, but this is to be expected for the price.
PROS
- Cheap
- Easy for Beginners
- Very easy to read the temperature
- Accurate for a thermometer of this style
- No batteries needed
CONS
- Lacks precision
5. Lifegard Aquatics Digital Temp Alert
Product Highlights
The Lifegard Aquatics Digital Temp Alert has a large digital display that shows both your aquarium and room temperatures simultaneously to 0.1 degrees. You can switch between Celsius and Fahrenheit.
The display and sensory probe are mounted on your tank using suction cups and are connected by a long cord. An alert feature sounds an alarm if the temperature gets too high or low.
Features
- Alert feature
- Suction cups for mounting
- Precise to 0.1 degrees
- Choose between Celsius or Fahrenheit
What We Like About Lifegard Aquatics Digital Temp Alert
The temperature appears on the screen in very large numbers, making it easy to tell the temperature from further away.
The alert feature lets you set an upper and lower temperature limit. If the temperature goes above or below these boundaries, an alarm will sound. This will improve your reaction time to temperature changes and could save your fish.
What We Don’t Like About Lifegard Aquatics Digital Temp Alert
The display is easy to read but this can quickly change as light levels drop. The screen is not backlit so can’t be read in the dark.
The main display will likely break if it comes into contact with water, so don’t accidentally drop it in your tank.
PROS
- Very clear screen
- The alert could save your fish
- Measures aquarium and room temperature simultaneously
- Accurate and precise
CONS
- The LCD display is not backlit
- Not waterproof
6. UPLY Digital Aquarium Thermometer
Product Highlights
This is a digital device that sits inside your aquarium. It is fully waterproof with an in-built temperature sensor, which alleviates the need for wires. Measurements are given with high precision and are easy to see due to the use of larger numbers.
Features
- Waterproof digital display
- Sits inside aquarium
- Precise to 0.1 degrees
- Wireless
- Temperature range of 58-158°F
What We Like About UPLY Digital Aquarium Thermometer
The large digital display on the UPLY Digital Aquarium Thermometer is easy to read due to the large numbers. Operating the device is simple too.
The thermometer is submerged in the water because it has a built-in sensor. This removes the need for wires, making your fish tank look less messy.
What We Don’t Like About UPLY Digital Aquarium Thermometer
The product feels cheaply made using low-quality materials. This is also evident through its function; many people report that the thermometer breaks soon after purchase.
The suction cup can be frustrating since it is easy for the device to fall from the aquarium wall.
The digital display is not backlit so reading the temperature in dim lighting is difficult.
PROS
- Display is clear with large numbers
- No messy wires
CONS
- Unreliable suction cup
- Prone to breaking
- Cheap, plastic appearance
- Display is not backlit
7. AODE Digital LCD Aquarium Thermometer
Product Highlights
This is a small digital device that has two parts to be mounted on your aquarium using suction cups. An LCD display to be put outside of the tank, and a sensory probe to be placed in the water. The two are connected by a long cord.
The display is clear and shows measurements to 0.1 degrees; they can either be in Celsius or Fahrenheit.
Features
- Can switch between Celsius and Fahrenheit
- LCD digital display
- Precise to 0.1 degrees
- Long cord between components
What We Like About AODE Digital LCD Aquarium Thermometer
This product is cheap and does what you’d want it to do for the price. Accurate temperature readings are given to a good precision and shown on a clear digital screen.
The screen can be turned on and off to save battery.
Suction cups make it easy to mount the components and the long cord makes it easy to place each part where you want it.
What We Don’t Like About AODE Digital LCD Aquarium Thermometer
If there isn’t much light in the room, it can be difficult to see the digital display, but a backlit screen is characteristic of more expensive devices.
You must use batteries to power it, so make sure you can replace them when they run out. The product does come with batteries included though.
PROS
- Components easily mounted with suction cups
- Good precision and accuracy
- Clear digital display
- Cheap
- Small and light
CONS
- Display not backlit
- Can’t use a power outlet
8. POPETPOP LCD Digital Aquarium Thermometer
Product Highlights
The POPETPOP LCD Digital Aquarium Thermometer is comprised of a small circular LCD display and a sensory probe, which are connected by a thin wire. Three pieces of information are shown on the screen: the current temperature, the previous maximum temperature, and the previous minimum temperature. The device is easy to operate, there are only two buttons.
Features
- Circular LCD Screen
- Switches between Celsius and Fahrenheit
- Saves maximum and minimum readings from past tests
- Attaches with suction cup or spring clip
- Tough and eco-friendly ABS shell
What We Like About POPETPOP LCD Digital Aquarium Thermometer
The circular display has a diameter of just 2.8 inches, so it doesn’t distract from the rest of your aquarium. It is easy to mount in place too, with either a suction cup or the spring clip.
Temperatures are given accurately and to 0.1 degrees of precision. There are only two buttons, so it isn’t confusing to use.
The screen is very clear too, showing the current temperature and past maximums and minimums.
What We Don’t Like About POPETPOP LCD Digital Aquarium Thermometer
The wire connecting the sensory probe can look untidy because it dangles in the water with no way to attach it to the glass.
The digital screen has no backlight, so your room needs to be well lit to see the readings.
PROS
- The small size saves space on the glass
- Easy to mount
- Simple 2-button operation
- Accurate and precise (0.1 degrees)
CONS
- No way to attach waterproof probe
- LCD display isn’t backlit
9. JCreate Aquarium Thermometer
Product Highlights
The JCreate Aquarium Thermometer boasts a transparent digital display with large numbers to contrast against your aquarium light. There are no messy wires, the device simply adheres to the glass of your tank.
You can use the touch screen to set up the flash function, which lets you know if the temperature falls outside of your ideal range.
Features
- Transparent digital display
- Touch screen
- No probes or wires
- Precise to 0.1 degrees
- Flash function
What We Like About JCreate Aquarium Thermometer
This thermometer has a very clear display. Your aquarium acts as a backlight, which makes it easy to read the large numbers.
The device looks smart, and since there are no wires, your tank will look smarter too.
There is a flash function that allows you to set an upper and lower temperature limit. If the temperature leaves this range, a light will flash to let you know.
What We Don’t Like About JCreate Aquarium Thermometer
Unfortunately, the battery life is quite short and will need replacing regularly. This can be frustrating, so you need to stock up on batteries.
The display is clear when the aquarium light is on, but without it, the large numbers become harder to read.
PROS
- The transparent screen doesn’t block the view of your aquarium
- No messy wires
- Clear display with large numbers
- Flash function could save your fish
- Accurate measurements
CONS
- The transparent display can be hard to read if your tank isn’t lit
- Short battery life
10. SUKRAGRAHA Traditional Stick-on Thermometer Strip
Product Highlights
This thermometer is ideal for beginners. The vertical strip is easy to stick to the outside of your aquarium. The temperature is clearly shown in both Celsius and Fahrenheit using various colors. This is a 10-piece set so you get plenty of spares if something goes wrong.
Features
- Adheres to the outside of the aquarium
- Different temperatures show as different colors
- Shows Celsius and Fahrenheit
- 64-93°F (18-34°C) range
- 10-piece set
What We Like About SUKRAGRAHA Traditional Stick-on Thermometer Strip
This is a simple design that is used by many companies. It is easy to attach and will constantly measure the tank’s temperature.
The use of color is an attractive addition.
The delivery arrives as a set of 10 thermometers. You may not need this many, but it is always nice to have spares, especially since you are not paying much for them.
What We Don’t Like About SUKRAGRAHA Traditional Stick-on Thermometer Strip
Without a probe in the water, the accuracy of the temperature readings can be questionable. The temperature is also only given to the nearest degree.
The colors are not as bright as marketing images may suggest. You must get up close to see the temperature, which is even more difficult in low-light environments.
PROS
- Cheap
- Easy to attach
- No batteries needed
- Comes as a set of 10 thermometer strips
CONS
- Not very precise
- Difficult to read
Final Verdict
As you can tell, there are many kinds of thermometer out there on the market. Each one will appeal to somebody.
Analog thermometers (such as the Marina Deluxe Floating Thermometer with Suction Cup) are great for people keeping fish for the first time. They are cheap, simple and effective.
However, if you can afford to spend a little more, digital thermometers are easier to read and offer greater precision.
I would recommend the JCreate Digital Aquarium thermometer. It looks smart and is easy to use, but most importantly, it gives accurate temperature readings.
It also has a useful flash feature, which lets you know if your aquarium’s temperature is at dangerous levels. This could be the difference between life and death for your fish.
If your aquarium is at the right temperature, it will be much easier to keep the environment healthy.
Useful. I bought the second place thermometer. I am surprised first place went to a device that lacks accuracy, surely that is the prime function of a thermometer & it has failed?
I just had a heater stop working and panicked that my fish may die (one did), so rushed to buy a new one. I decided to splash out on the expensive Fluval one with built in thermometer and temp control and am really glad I did. It takes away one step of worrying that the heater is set too high or too low etc, and gives peace of mind. I am assuming (hopefully correctly) that the higher cost also includes a quality product. Whilst it maybe should not have been included in the above article, it seems worth pointing out the existence of these heaters I think, as I would not have just bought a £10 thermometer a couple of weeks ago, instead putting that £10 towards the heater cost.