Best Aquarium Thermometers 2022 - Buyers Guide & Reviews

1. Zacro	2. Zoo Med	3. Qooltek

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For the uninitiated, fishkeeping might look really simple. You buy a tank, put some colorful fish in, and enjoy them as they grow. But the truth is that it’s so much more than that. While most fish don’t need constant care, setting up an aquarium for them first requires good research and testing. You may also need additional pieces of equipment to closely monitor and maintain the environment inside.

One of the many important parameters that needs to be regulated is the temperature of the water inside the tank. Most tropical fish require temperatures around 77 °F (25 °C) for survival. If your aquarium is not in a room in the 75 to 80 °F (24-27°C) range, the heater in your tank can be used to manipulate it to correct levels. Sometimes, it might also include a thermometer to display current reading, which isn’t always accurate.

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To keep your pets healthy and happy, you want to make sure their water is neither too cold nor too warm. This is especially vital in the case for more delicate fish, as the wrong temperature could potentially kill them. Which is why you need to get the best aquarium thermometer out there, and not depend on the one included in your kit.

Because there are so many options out there, selecting one can feel overwhelming. But not all thermometers are made the same, so if you know the kind you want and what each one offers, selecting one will be a joyride, which is exactly what this guide will do. First, we’ll see the 5 things you should take into account while deciding the best aquarium thermometer. Then, we’ll talk about the 11 best ones in the market currently, and everything they offer and all that they fail to.

Factors To Look For When Buying The Best Aquarium Thermometer

1. Range

Many types of fish don’t have the ability to regulate their own body temperature, and so they rely on the environment around them to do it for them. So, it’s important to ensure that the thermometer you buy is able to detect even extreme temperatures that some types of fish may require. Which is why, as a general rule, the wider the range it can detect, the better.

If you’re only going to have tropical fish, one with a large range is ideal. Ensure that it can detect temperatures ranging from 50 degree Fahrenheit (10 degree Celsius) to 104 degree Fahrenheit (40 degree Celsius). This kind of range is essential, like in the case of freshwater fish who can undergo a fluctuation of about 30 degrees Fahrenheit each day.

2. Ease Of Installation And Use

Using a thermometer sounds easy enough, but you want to check how it works anyway. It’s also important to ensure that it’s easy to set up, because complex procedure just means there’s a lot that can go wrong, and you might end up getting the wrong reading. There are quite a few types out there, and it helps to be aware of each.

Stick on thermometers (or fermometers) usually come as a part of your freshwater aquarium kits. They are to be stuck onto the outer glass on the side or front of your aquarium, where it’s convenient to read. They have a scale that is quite easy to read.

Standing or floating thermometers are placed in direct contact with the water. Depending on the model, they either sink to the bottom of the tank, float on top, or hang on the side with a clip or a suction cup. As long as it stays in place, you don’t have to worry about anything.

Finally, digital thermometers. They usually have two parts: a digital display and a probe. The probe is usually placed inside the aquarium, and the display is stuck outside using a suction cup. The connection between probe and display can be wireless or wired. It works on battery or sometimes needs to be plugged into a wall socket.

Sometimes, the display part can also be submerged in water, but this is not usually the case. So make sure you read the setup instructions correctly and carefully. Make sure the cord length provided will be sufficient to connect it all. A few models also offer a nice feature that alerts you when the temperature goes above or below a set range.

3. Accuracy

It can cause great distress to the fish if the temperature of the water goes even slightly above or below their preferred range. That is why a thermometer that provides a temperature as accurate as possible is desirable, to keep the sensitive fish happy.

Of the three types, stick on thermometers are found to lesser accurate. If they’re placed in direct sunlight or near cooling or heating vents, it can significantly alter the reading. Sometimes, room air temperature can also affect their accuracy. The most accurate types are digital thermometers, usually accurate to within +/- 1 °C.

4. Temperature Readability

A clear display with numbers and unit displayed large enough to read from a distance is preferable. Floating or standing temperatures that go inside the tank, usually have a smaller print of readings on them, making it hard to read. Some do come with colored zones, helping you get a quick idea of a range.

Digital and stick on thermometer models tend to be the clearest and brightest to read. However, some models offer only one temperature scale, either the Celsius or Fahrenheit, which can turn out to be a deal breaker if you’re not used to one.

5. Durability

As a general rule for all the things you buy for your aquarium, the material it is made up of is very crucial. They have to remain accurate, long-lasting and be quite durable. This is especially necessary for equipment that stays in the water, as breakage can result in a build-up of chemicals in the tank, and severely harm the inhabitants.

If it’s accurate but not durable or without a good warranty cover, it’s not a good investment. A thermometer is not something you should need to constantly purchase: they are supposed to last. You don’t want to buy a cheap mercury thermometer and have it leaking toxic mercury into the tank.

Floating or standing temperatures, that are in direct contact with water, are usually made of glass. As this means the fish can touch and play with it, glass is not a good option if you have large boisterous fish. But if it’s built strong enough, and the fish are mostly tame, then there should be no problem.

For digital thermometers, inclusion of extra batteries is always a bonus. Some include a display part which is usually not waterproof like the probe. So it’s important to be a little cautious using it. In models where even the display can be placed inside the tank, battery leakage might occur.

Top 11 Best Aquarium Thermometers 2022

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

Package contains

2 Probes
2 Digital Thermometers
2 Batteries

Reasons to buy

Provides reading in either temperature scale
Precise reading
Easy to use and operate
Excellent customer service

Reasons to avoid

It can take a while to measure the temperature
The entire body isn’t waterproof

To ensure your fish get the perfect environment, you need the best aquarium thermometer you can find, and that’s the Zacro LCD Digital Aquarium Thermometer. It’s made to be used in all kinds of fish tanks, including marine water, saltwater, freshwater and tap water. The batteries it uses are LR44, and two are included in your purchase.

The gadget is basically two parts: probe and display. Only the probe part needs to go inside the water, because the display isn’t waterproof. It has to be stuck outside the tank using the suction cup provided, which works efficiently. There’s two full sets provided, so you always have a backup handy.

It can detect temperatures in a pretty impressive range quite accurately so you can ensure your fish are never too cold or too hot. The LCD display screen is big and bright enough so you can read the measurement clearly without having to strain. However, it’s not backlit, so you can’t see it well if the room is dark. Additionally, you can switch between Celsius and Fahrenheit mode and choose what you find easiest.

Overall, it’s easy to set up and use. With a warranty cover of eighteen months, you can use it for a long time without worrying. For the price it comes at, it’s definitely worth a buy.

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2. Zoo Med Digital Thermometer

Specifications: Thermometer size: 3 x 2 x 1 in | Cable length: ~39 in | Temperature range: 10 °F to 140 °F ( -23 °C to 60 °C) | Warranty: 12 months

Package contains

1 Probe
1 Digital Display
1 Battery

Reasons to buy

Provides reading in either temperature scale
Precise and quick reading
Easy to set up and use
Long probe cord

Reasons to avoid

First reading after turning on is slow
Conversion readings may not be accurate

This is the best aquarium thermometer that is versatile enough to also be used in a variety of other habitats is the Zoo Med Digital Thermometer. It comes with a probe and a digital display, both of which can be submerged in water. The display, if you prefer, can also be stuck outside using the suction cup provided. One set of batteries is also included to start you off.

The probe card is long enough, making it suitable for big and small tanks alike. It works well in both freshwater and salt waters, as well as reptile incubators and terrariums. The design might not be the prettiest on the outside, but it works with pinpoint accuracy – being accurate to within +/- 0.5 degrees Celsius.

It’s quite durable – as long as your pet doesn’t chew the cord. In cases of technical issues, it’s covered by the warranty for a year. It’s very easy to use – just press the ‘pwr’ button to turn it on, and long press about 5 seconds to turn it back off. It’s also very easy to switch between Celsius and Fahrenheit units.

This item is very popular among aquarium owners, and the affordable price it comes at is a bonus. The suction cup might eventually weaken or not stick at all on wooden surfaces, but other than that this thermometer is extremely reliable and will serve you for at least a couple of years.

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3. Qooltek Digital LCD Thermometer Temperature Gauge Aquarium Thermometer with Probe for Vehicle Reptile Terrarium Fish Tank Refrigerator (Fahrenheit)

Package contains

1 Probe
1 Digital Display
2 Cell Batteries
1 Manual

Reasons to buy

Precise and quick reading
Easy to set up and use

Reasons to avoid

Only displays in Fahrenheit
Large LCD display
No power switch

If you would like a mini thermometer that inconspicuously hangs on the side of your aquarium and does its job, this digital thermometer by Qooltek might just be the one for you. The probe is kept in water and the display is hung outside to display temperatures. The display is not waterproof, and there is no suction cup provided.

There is no switch to conveniently turn it on or off, which means you have to remove and put the batteries back with each use. It only displays in Fahrenheit, which can be a downside for some people. However, there are users who claim that it’s possible to tweak the circuit to display temperature in Celsius.

The thermometer shows pretty accurate readings, with an accuracy within +/- 2 degrees Fahrenheit. This is especially good for use in freshwater fish tanks, not so much for saltwater aquariums. The screen displaying the readings is small, so it might be a little struggle to see temperature, especially if you’re looking at it from a distance.

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4. Ethmeas Digital Thermometer and Hygrometer for Reptiles Terrarium pet keeping, Digital Indoor Outdoor Temperature Gauge and Humidity

Package Contains

1 Hygrometer and Thermometer
1 Battery
1 Manual

Reasons to buy

Multipurpose
Provides reading in both temperature scales
Accurate

Reasons to avoid

Not specifically designed for water tanks
Hygrometer isn’t very good
Not very durable

If you would like a product that can tell you both the temperature, as well as the humidity of a place, you will like Ethmeas Digital Thermometer and Hygrometer. It’s specifically designed to monitor humidity and temperature of terrariums and reptile incubators, but it can also be used to measure temperature of water in a fish tank. The good news is that its made entirely of environmentally friendly products.

It consists of two probes, one that detects humidity, and the other detects temperature. Each has its own suction cup to help you keep it in place by mounting it. The LED display also features multiple mounting options: a retractable tabletop stand, a retractable clip and a magnet. You can use any of these depending on the situation.

Using this tool is really simple. There’s a button to switch between Fahrenheit and Celsius, as well as a button to turn it on. It takes about ten seconds to measure, and gives accurate results with +/- 5% humidity levels and +/- 1 °C temperature. It has a memory feature that can recall minimum and maximum recorded history.

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5. Aquaneat Aquarium Digital Thermometer Fish Tank Water Terrarium Black Free Extra Batteries

Specifications: Unit size: 2.3″ (L) x 1.5″ (W) | Cable length: 3 feet | Temperature range: -58 °F to 158 °F ( -50 °C to 70 °C) | Weight: 1.12 ounces

Package contains

3 Probes
3 Digital Display Screens
6 Cell Batteries
1 Manual

Reasons to buy

Cheap
Provides reading in both temperature scales
Wide temperature range
Wide application

Reasons to avoid

Might not be accurate sometimes
Weak suction cup

The best aquarium thermometer you can get at an unbelievably cheap price is the Aquaneat Aquarium Digital Thermometer. It can give you an idea of the temperature in your terrarium, reptile tank, vivarium, saltwater tank or freshwater aquarium. Additionally, it works just as well in deep freezers, chillers and refrigerators. It’s incredibly simple to set up: just put the probe in water and make it stay using the suction cup provided. It might be a bit of a hassle making it stay as it doesn’t always seem to stick.

Owing to the small size of the screen and the long cable length, the whole setup remains fairly unobtrusive and inconspicuous. It’s easy to use: all you have to do is press a button to turn it on or off. It is also really easy to switch between the two temperature units. The LCD display is big enough to display the reading clearly. It has an accuracy within +/- 1°C.

The probe works very well even in high moisture environments. However, the display isn’t waterproof, so necessary care is required. The package ships with 3 thermometers and six cells of battery so that you have a spare for each and always prepared.

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6. Jcreate Fish Tank Thermometer, Touch Screen Digital Aquarium Thermometer with LCD Display, Stick-on Temperature Sensor ensures Optimum Temperature in Terrarium, for Your pet Amphibians and Reptile

Specifications: Unit size: 76 * 76 * 7 mm | Temperature range: 32 °F to 158 °F (0 °C to 70 °C) | Warranty: 12 months

Package contains

1 Digital Thermometer
2 CR2032 Batteries

Reasons to buy

Ease of use
Extremely functional
Provides reading in both temperature scales
Alerts you when the temperature is too high or low

Reasons to avoid

Not meant for acrylic aquariums

Do you feel like wires mess up the aesthetic appeal of your aquarium? Then consider buying the jcreate Fish Tank Thermometer. It’s the best aquarium thermometer with a simple design and no wires at all. It sticks outside on the glass of your fish tank and detects temperatures of an accuracy within 0.1 °C. It’s suitable for a variety of purposes: in vivariums, greenhouse, terrariums, wie barrels, marine water tanks, salty waters, tap water as well as fresh water aquariums.

The sensor part of this wireless thermometer faces inside. The outside, a nice red and black color, is the touch screen display. The screen is big, and displays digits clearly. It’s turned on or off by inserting or removing the cell. You can switch between Fahrenheit and Celsius using the arrow key.

A very useful feature of this thermometer is the alert system. It lets you set a certain minimum and maximum temperature. If the water is higher or lower than this, it begins flashing so you can adjust your heater immediately and avoid causing distress to you pets.

It’s ready to use right out of the box, with the battery already inserted. There’s also a spare for when the first one runs out. The product is also covered by a 12 month manufacturer’s warranty. So if you have a glass tank and would like to add a unique, affordable and elegant tool to measure temperature, this is the one for you.

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7. Ketotek Digital Thermometer Temperature Meter Gauge Waterproof Sensor Probe Aquarium Car PC case Power Bank Temp Meter Celsius/Fahrenheit LCD Display °C/°F PC MOD (Digital Thermometer with USB)

Specifications: Unit size: 1.85″ x 1.1″ x 0.6″ | Cable length: 40 in | Temperature range: -58 °F to 230 °F ( -50 °C to 110°C) | Warranty: 24 months

Package contains

1 Probe
1 Digital Display
2 Cell Batteries
1 Manual

Reasons to buy

Multiple applications
Provides reading in both temperature scales
Extremely accurate
Very bright display

Reasons to avoid

USB adapter is not included
Difficult to mount

The best aquarium thermometer with a USB connector is the KETOTEK Digital Thermometer. It’s not just meant for use in your fish tank, but also in your engine room, car, computer or anywhere outdoors, to monitor or check water heaters, refrigerators, car water, air-conditioning and more.

The NTC probe helps detect temperature with great accuracy, with an error margin of only +/- 0.5°F. It also has an extremely wide temperature range.

It keeps rechecking temperature every few seconds, and shows it on the display screen. This is mounted outside, using your own creative ideas. The most popular one is to stick it using Velcro. The screen is extremely bright, making it possible to read the numbers even under bright sunlight. There’s a jumper switch at the back to change between Celsius and Fahrenheit, which can be inconvenient sometimes depending on how you mount the display.

The cord length might feel short at only 40 inches, but it’s understandable given that this is USB. There’s no USB adapter included. To turn it off, you take off the USB. It’s accuracy and beautiful design is more than worth the affordable price it comes at.

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8. Lifegard Aquatics Digital Temp Alert

Specifications: LCD Dimension: 4 * 4 in | Cable length: 3 feet | Temperature range: -58 °F to 158 °F ( -50 °C to 70 °C) | Warranty: 12 months

Package contains

1 Probe
1 Digital Display
1 Battery
1 Manual

Reasons to buy

Large display
Alert system if the temperature is too high or too low
Works in saltwater fish tanks as well
Long lasting

Reasons to avoid

Only shows temperature in Fahrenheit
Display not easy to read during night
Not super accurate

It’s really convenient to see the reading from a distance. It works not just in fish tanks, but also green houses and reptile incubators. It has the ability to display both room temperature (called “in”) and water temperature (“out”).

It consists of a probe that is to be placed in water using the suction cup provided. It’s covered with cheap material that can corrode easily depending on where it’s used. The LCD display has a small retractable stand and an adhesive stick pad so you can place it on a surface or stick it in on wherever required. It’s not waterproof at all, so you want it to keep it safe from splashes and wet areas.

It comes with a rather useful alert system that can feel challenging to learn. There are four modes you can set:

High-temperature alert only (Probe).
Low-temperature alert only (Probe).
Both high and low-temperature alert (Probe).
Both high and low-temperature alert (Room).

So, you can see how customizable it is. Whenever it goes out of set range, the screen with flash lights and also give you a sound alert so you can fix it immediately. It all works on a AAA battery. There are no spares included.

It can detect temperatures over a wide range, and is suitable for use in both freshwater as well as saltwater aquariums. The accuracy is decent. It only displays Fahrenheit readings, which can be difficult if you’re used to the Celsius scale.

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9. Fluval Wireless 2in1 Digital Thermometer

Specifications: Dimension: 0.5 x 2.6 x 4.9 inches | Temperature range: -58 °F to 199 °F ( -50 °C to 92.8 °C) | Operation temperature: -14 °F ~ +122 °F | Weight: 36.3 grams | Warranty: Yes

Package contains

1 Digital Display
1 Manual
1 Cell Battery

Reasons to buy

Large display
Provides reading in both temperature scales
Works in saltwater fish tanks as well
Easy to set up

Reasons to avoid

Not cheap
Not super accurate

With advancements in technology, we like gadgets that make things easier and don’t take a lot of effort to set up. This makes the Fluval Wireless 2 in 1 Digital Thermometer the perfect addition to your glass tank. There are no wires or probes you need to take care of; just an LCD screen that promptly and tightly sticks anywhere on your tank.

The sensor records the temperature of water in your fish tank with low margin of error and decent accuracy. It’s made for both freshwater as well as saltwater aquariums. If your fish need to be kept at a certain temperature, and will not do well in a wider range, give this thermometer a miss. It is, however, more accurate if your glass is thinner.

It also displays ambient room temperature. This is important, because room temperatures change easily and in turn affect water temperatures of small tanks. Even if you don’t have a heater to control water temperature in your aquarium, knowing the air temperature can help you decide what changes you need to make.

It’s easy to switch between Fahrenheit and Celsius modes. The display is large enough so that you can read it clearly even from a distance. So if you like a wireless, neat option to measure temperatures, and don’t mind paying a little extra for a good brand name with warranty, get this thermometer.

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10. Inkbird Heating Thermostat Aquarium Reptile Submersible Probe Sensor ITC306T Relay Digital Greenhouse Temperature Controller Dual Stage Timer Switch Only Heat Plug Outlet No Cooling

Package contains

1 Probe
1 Temperature controller
2 Cell Batteries
1 Manual

Reasons to buy

Very wide temperature range
Works in saltwater fish tanks
Long lasting

Reasons to avoid

Tricky to set up

If you want to take temperature monitoring a step further, consider getting the Inkbird ITC-308 Aquarium Temperature Controller. It might look more intimidating and complex than all the other thermometers above, but that’s because it does more work. The latest model even comes with Wifi. It’s unmatched in the features it offers.

Basically, what it does is that it checks and controls the temperature of your heater. You set a temperature range, or two temperatures (for day and night) and the thermostat will take care of the rest. At all times, you can see the set temperature and current measures temperature on its display. Both Celsius and Fahrenheit readings are available.

It’s not a heater itself, but it plugs into the heater and controls it. As long as you calibrate it first, it will show you accurate temperatures and work very smoothly. The only problem with the probe is that there is no suction cup or any other mounting device.

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11. Capetsma Aquarium Thermometer with Sound Alarm, LCD Fish Tank Thermometer Monitor Water Temperature with Accurate Temperature Sensor, Digital Temperature Gauge for car, Room and Terrarium

Specifications: Unit size: 3.0 * 2.6 * 0.7 inch | Temperature range: -32 °F to 158 °F ( 0 °C to 70 °C) | Warranty: 12 months |

Package contains

1 Thermometer
1 Manual

Reasons to buy

Wireless
Easy to read

Reasons to avoid

Low alarm volume

If you’re not fond of wires and probes but still want a fairly accurate reading of the temperature inside your aquarium, consider getting the Capetsma Aquarium Thermometer. It consists of a big LCD display screen that can be placed on table tops or stuck to the sides of your glass tank.

The function keys allow you to set an alarm for when the temperature goes below or above the preferred range. It will flash lights and beep quietly for sixty seconds to alert you so you can take quick action. There’s a default low and high already set, but you can change it easily.

The readings are quite accurate, with a ± 0.5°C /± 1°F margin of error. It can be used in all types of aquariums and fish tanks – marine water, saltwater, tap water and freshwater. The power source is a battery, which is not included in the pack.

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Best Aquarium Thermometer: What’s Your Pick?

An aquarium thermometer is one of the many essential tools every fish tank owner needs, beginner or not. This is because not only do they constantly tell you the temperature of the water, but some even alert you when something seems wrong. So getting one that displays accurate readings, preferably with the alert feature, is what you should go for. Being able to detect room temperatures is a bonus some offer.