Stephen is an owner of several aquarium supplies shops in New York. Like no one else, he knows how to pick the perfect fish tank or any aquarium accessory from pump to artificial decorative plants.
Last updated: July 14, 2021
If your pet fish could communicate, what do you think they would say? Many owners might be surprised to learn that they might have some complaints about the water temperatures in their tank. Believe it or not, not all aquarium thermometers are created equal, and finding the right one could make a huge difference in your fish’s tank— and their happiness. All it takes is a little research, and before you know it, your fish will be doing flips in their tank to thank you!
Lucky for you, we’ve taken all the work out of finding the best aquarium thermometers and narrowed them down to one simple list. Our review takes into consideration all the different types of aquariums one could use and which aquarium thermometers are most suitable for them. From the dimensions and weight of the tank to the temperature range and cable length of the thermometers, we’ve ensured you will end up with the best aquarium thermometer for you.
JCreate Aquarium Thermometer
"This thermometer has a large and easy to read display.Wide usage.LCD touchscreen."
"This unique high-powered tool has a continuous heating alarm.Two probes.App."
Inkbird Wireless Thermometer
"Another thermometer that comes with a convenient and easy to use App.Flexible.Accurate."
Aquarium Thermometer by Atsani
"This is a stick-on aquarium thermometer that offers a long working time.LCD screen.1-year guarantee."
Most Aesthetically Pleasing:
Qguai Aquarium Thermometer
"Widely applicable, this thermometer doesn’t need a cable.Easy to use.Accurate."
FREESEA Aquarium Heater
"This aquarium thermometer offers an intelligent temperature control.12-month warranty.Versatile."
Easiest to Install:
POPETPOP LCD Digital Aquarium Thermometer
"Highly precise, this thermometer is made from eco-friendly material.LCD display.Easy to install."
Second Best Value:
Zacro Pack of 2 LCD Digital Aquarium Thermometers
"It’s a pack of two very compact and easy to use thermometers.Easy to read.Good deal."
VIVOSUN 4-Pack LCD Digital Aquarium Thermometer
"This is a pack of four adjustable and accurate thermometers.Durable.Long cable."
Top 9 Aquarium Thermometers Review 2021
JCreate Aquarium Thermometer – Editor’s Choice
Dimensions: 3 x 3 x 0.3 inches
Weight: 0.63 oz
Temperature range: 0°C to 70°C / 32°F – 158°F
Cable length: no cable
More features: large numbers; accurate display; easy to use; wide usage; LCD touchscreen
For those of you who want a straightforward and easy to read interface, this digital aquarium thermometer is the one for you. The small and easy to use thermometer simply sticks on to your tank and gives you an almost immediate reading. The JCreate Aquarium Thermometer only requires a battery to use and frees you of all the messy wires and probes you might typically find on an aquarium thermometer. In order to insert the battery, you simply pull down the red battery cover and pop it right in. Even your kids could do it! The digital interface also features large numbers, making the tank’s temperature that much easier to read. This digital aquarium thermometer isn’t exclusive to fish tanks either. It is also suitable for your reptiles, whether they be lizards, snakes, or turtles. Have no pets? No problem. This aquarium sticker thermometer even works with greenhouses, so you can sleep well at night knowing your plants are kept at a comfortable temperature all day long. If you are looking for the best digital aquarium thermometer with the most accurate reading for your pets or plants, look no further. The JCreate Aquarium Thermometer has got you covered!
Why are we impressed? The easy to read display and accurate temperature reading are certainly some of this thermometer’s best features.
What negatives must you be aware of? The thermometer has been known to not work on some acrylic tanks.
Inkbird C929A – Premium Pick
Dimensions: 5.5 x 3.3 x 2.7 inches
Weight: 8.01 oz
Temperature range: 20.0℃ to 35.0℃ / 68.0℉ – 95.0℉
Cable length: not specified
More features: high-powered; two probes; dual protection; APP notification; continuous heating alarm; LCD display
It’s 2020, which probably means that you’ve upgraded all of your household electronics to their latest models. So why not upgrade your aquarium thermometer and heater too? Enter the Inkbird C929A- with its WiFi capabilities and continuous heating time alarm, you’ll be left wondering why it’s taken you so long to get it. The dual-probe aquarium heater has the capability to pair with your phone and send push notifications anytime something is amiss in your aquarium. No more constant worrying about the safety of your fish, the Inkbird C929A has got you covered. Because of the dual probes, your aquarium’s temperature will always be as accurate as possible. To get started with your new fish aquarium thermometer, simply plug it in. From there, you’ll be able to start controlling the temperature of your aquarium’s water almost immediately. Once you’ve got the App set up on your phone, you’ll be able to start heating up your tank and adjust it as needed. If anything were to go wrong with your device, the Inkbird C929A comes with a two-year warranty on your controller and a one-year warranty for the dual probes.
What stands out? The aquarium thermometer is easy to use, and we love the option to control the device from your phone!
What cons did we manage to find? The Inkbird C929A doesn’t allow for cooling, only heating.
Temperature range:–40~140°F/-40~60°C (inner sensor), -40~212°F/-40~100°C (external probe)
More features: flexible; comes with an App; can support multiple devices; accurate; LCD screen; Bluetooth connection
If you’re looking for an aquarium thermometer that can give you quick but accurate results, the Inkbird Wireless Thermometer is the one for you. The Bluetooth enabled device displays not just temperature but also the humidity levels in your tank. Complete with an app for your phone, you’ll wish you had purchased this sooner. Using your phone, you can monitor the humidity and temperature levels via the probe on the device. The App, which is available in more than one language, provides you with all types of data, including when your aquarium thermometer needs its batteries replaced. And yes, you can control more than one device via one phone, and vice versa. An alarm will also sound on your phone when humidity levels are too high. The thermometer has a magnetic back, which makes it easy to attach to your tank, and comes with a one-year warranty. While the probe is waterproof, the device itself isn’t, so you may want to be careful when placing it near your aquarium.
What do we love it for? We love how easy this device makes monitoring the humidity and temperature levels on your tank!
What were we disappointed with? The digital aquarium thermometer isn’t entirely waterproof.
Aquarium Thermometer by Atsani – Honorable Mention
Dimensions: 3.94 x 3.94 x 3.94 inches
Weight: 3.53 oz
Temperature range: -10°C to +50°C
Cable length: 1 m
More features: LCD screen; stick-on; easy to use; long working time; 1-year guarantee
Let’s face it- aquarium thermometers aren’t always the most attractive, especially compared to the beautiful creatures they help monitor. Luckily, Atsani has come up with a solution. Their sleek and easy-to-use LCD aquarium thermometer is a pet owner’s dream come true. The LCD screen beautifully displays the tank’s water temperature, the indoor temperature and even tells you how much battery life your thermometer has left. The screen is even easy to read at night without having to turn on any obnoxious lights. The thermometer’s instructions are simple and easy to follow. Stick it on to the tank, lower the probe into the water, and voila, it will display the temperature, whether in Celsius or Fahrenheit. The aquarium thermometer comes with its own LR 44 battery and a one-year warranty to make sure you’re completely satisfied with the product.
Why are we impressed? The aquarium thermometer has a sleek look that will fit right in with any tank or terrarium. The display is large and can be read even at night.
What negatives must you be aware of? Does not come with a replacement battery and the original battery only lasts five months.
Qguai Aquarium Thermometer – Most Aesthetically Pleasing
Dimensions: 3 x 3 x 0.28 inches
Weight: 1.76 oz
Temperature range: 0°C – 70°C / 32°F – 158°F
Cable length: no cable
More features: LCD screen; accurate; easy to use; wide application
There’s no denying it; an aquarium needs its own thermometer whether we like it or not. But just because it’s necessary doesn’t mean it can’t be discreet. That’s why we love the Qguai Aquarium Thermometer. The clear screen means you can easily check the tank’s temperature while still being able to keep an eye on your beloved fish. What’s even better is the fact that you don’t have to deal with any messy chords or worry about plugging in this aquarium sticker thermometer. It sticks right to the tank without leaving behind any sticky residue upon removal due to specially made insulative tape. Once attached to the tank, you can switch back and forth between Fahrenheit and Celsius by simply pressing up or down on the switch. The Oguai Aquarium Thermometer is not only aesthetically pleasing, but it will also make sure your fish’s tank is as accurate to their natural habitat as possible.
Why is it special? We love how this sticker thermometer looks on every tank!
What are the flaws? Unfortunately, this aquarium thermometer, although beautiful to look at, doesn’t last very long. However, Oguai does provide you with a six-month warranty should anything happen.
FREESEA Aquarium Heater – Most Waterproof
Dimensions: 7.9 x 3 x 2 inches
Weight: 7.37 oz.
Temperature range: 63°F~95°F
Cable length: 6.8 inches
More features: intelligent temperature control; 12-month warranty
If you’re an informed fish owner, you know that not all fish are created equal. That is, not every fish prefers the same environment. Some species prefer warmer waters, while others prefer their water temperature on the cooler side. So how can you know when you have the right temperature? By using a Freesea Aquarium Heater. This device allows you to heat up the water in your tank while also maintaining the right temperature for your pet. The aquarium thermometer will immediately stop heating once it reaches the set temperature, so you don’t have to worry about keeping an eye on it. Unlike other heaters, the Freesea Aquarium Heater is entirely waterproof and can be submerged completely in the tank. No matter the size of your fish tank, whether it be one or five gallons, the water temperature will remain as warm as you like.
What makes it stand out? The aquarium heater can be completely submerged in water, so there’s no need to worry about ruining it. Not to mention it also has a 12-month warranty!
Which disadvantages must you keep in mind? The heater has to be completely underwater for it to work.
POPETPOP LCD Digital Aquarium Thermometer – Easiest to Install
Dimensions: 2.76 x 2.76 x 1.18 inches
Weight: 1.8 oz
Temperature range: -20℃ ~ + 70℃
Cable length: 40 inches
More features: LCD display; highly precise; easy to install; eco-friendly material
If you’re a pet owner, chances are you know just how expensive it can be. Between food, toys, and providing them with a safe and healthy environment, things can add up. That’s why when shopping around for an affordable LCD aquarium, you may want to stop here. At just under $12, the POPETPOP LCD Digital Aquarium Thermometer is truly a bang for your buck. The thermometer can clip on to the tank or can be stuck on via its suction cup. Aside from giving you an accurate reading, being easy to use, and being durable, this thermometer is also eco-friendly. They are made out of an environmentally friendly material that covers and keeps the device safe. The POPETPOP LCD Digital Aquarium Thermometer also has a large LCD screen that makes the temperature easy to read. You can set it to whatever minimum and maximum temperatures you see fit for your pet. This LCD thermometer can be easily used in both saltwater and freshwater tanks.
What do we love it for? We love that this thermometer is eco-friendly! We also love how portable and easy to use it is.
What were we disappointed with? It isn’t entirely waterproof.
Zacro Pack of 2 LCD Digital Aquarium Thermometers – Second Best Value
Dimensions: 2.17 x 1.46 inches
Weight: 2.08 oz
Temperature range: -50℃ ~ + 70℃
Cable length: 24.88 inches
More features: pack of two; compact; easy to operate
If you’re looking for straightforward, no-frills saltwater or a freshwater thermometer, the Zacro LCD Digital Aquarium Thermometers are your best bet. The two-pack rings in at just under $10 and have their own suction cups making it easy to assemble and get to work. Unlike some of the more expensive aquarium thermometers, these do just what they’re intended to do— read the water’s temperature. The large LCD screen displays the temperature in either Fahrenheit or Celsius within one degree. Each thermometer also comes with a battery and a probe, allowing you to replace one when it stops working. This thermometer is ideal for those who don’t wish to spend their free time reading instruction manuals and simply want to maintain their tank’s temperature in the right setting.
What stands out? It comes in a pack of two, which means you get an automatic replacement when one gives out.
What cons did we manage to find? It’s not as aesthetically pleasing as other aquarium thermometers.
VIVOSUN 4-Pack LCD Digital Aquarium Thermometer – Best Value
Dimensions: 7.8 x 3.8 x 2 inches
Weight: 8.61 oz
Temperature range: -50℃ ~ +70℃ / -58 °F ~ +158 °F
Cable length: 78.74 inches
More features: LCD display; adjustable unit temperature; two suction cups; accurate; pack of four; durable
Are you tired of having to purchase aquarium thermometers over and over again? Wish you could simply buy them in bulk? Well, now you can! The VIVOSUN LCD Digital Aquarium Thermometer comes in a nifty pack of four, which means you’ll never be short of them. But wait, it only gets better from here! The display is large enough for even those with not-so-great vision, comes with an extra-long cable, is easy to adjust, and is easy to attach to any aquarium thanks to two suction cups. The thermometer also includes a long-lasting battery that won’t give up so easily.
Why is it special? These come in a pack of four, so you’ll never run out!
What are the flaws? The extra-long cable could potentially get in the way.
Things to Consider
So now that we’ve got all the research out of the way, it’s time to narrow done which aquarium thermometer is right for you. But before we do that, there are a few things to take into consideration first. For one, what type of thermometer is best for your fish tank? Do you prefer a smart thermometer with WiFi and Bluetooth capabilities or a simpler kind? How often do you tend to switch them out? Let’s start out by explaining why you even need an aquarium thermometer in the first place.
Why do you need an aquarium thermometer?
Whether you’re a first-time fish owner or an experienced one, it’s important to know just why aquarium thermometers are necessary. It’s a common misconception that only tropical fish need heaters in their tanks, but this couldn’t be further from the truth. All types of fish need their water to be at a specific temperature in order for them to survive.
Like humans, fish and other reptiles must maintain homeostasis, or equilibrium in their bodies to function properly, so the water must also maintain a stable temperature. However, there may be times when the temperature in your pet’s tank or aquarium might change overnight, and the only way to tell is by having a thermometer in place.
Features to consider before you buy an aquarium thermometer
As mentioned earlier, there are many things to consider before you purchase an aquarium thermometer. If your tank is on the bigger side, you might want a thermometer with a long cable that can extend as far as you need it to go. In this case, the VIVOSUN LCD Digital Aquarium Thermometer would be your best bet. For those who prefer to keep track of their aquarium via charts and data on their phone, you should consider the Inkbird C929A or the Inkbird Wireless Thermometer; both of which have a handy app you can install on your Android or iPhone. You may also want to research the type of fish you have in order to know what temperatures suit them best.
When you’re buying a fan or an air conditioner for your room or home, you take into consideration the size of the room before you make your purchase. After all, you want to make sure all areas of your house stay cool or warm, don’t you? Well it’s important to consider the same thing in your aquarium. When purchasing an aquarium thermometer, size matters. That’s why we like the FREESEA Aquarium Heater. This spiffy little guy is able to heat up almost any tank, whether big or small, and can even handle tanks of up to 25 gallons, but can also get the job done in tanks as small as one gallon.
Some aquarium thermometers are bigger and heavier than others. Neither is a bad thing- it just boils down to personal preference. When shopping around for the perfect thermometer, keep in mind how it will fit in your tank. Some thermometers like the Zacro LCD Digital Aquarium Thermometers are much bigger than others, but this makes them much easier to read. However, if you’re looking for something more inconspicuous, perhaps the JCreate Aquarium Thermometer would be much more suitable. Weighing in at just .63 oz and with a see-through screen, you’ll hardly notice it’s even there.
Not all aquarium heaters with thermometers will heat up the same. The range for some may be lower than others, and depending on the type of fish or animal that you have, you may need one with a higher range than others. In this case, we recommend either the JCreate Aquarium Thermometer, the Qguai Aquarium Thermometer, or the VIVOSUN LCD Digital Aquarium Thermometer. These all have the best range of all the thermometers reviewed.
If you’ve chosen to go with an aquarium thermometer that isn’t wireless, it means you’ve gone one with a cable. Both are equally good, but when choosing your thermometer, consider the length of its cable. The VIVOSUN 4-Pack LCD Digital Aquarium Thermometer has the longest cable by far at just under 79 inches, followed by the POPETPOP LCD Digital Aquarium Thermometer cable, coming in at 40 inches. These are both ideals for larger fish tanks.
Perhaps the most important thing to consider when choosing your aquarium thermometer is its accuracy. Even the smallest inaccuracy can cause a life or death situation for your pet. Given our research, the JCreate Aquarium Thermometer has proven to provide the most accurate readings compared to the other thermometers.
So now that you’ve chosen the thermometer that’s right for you, it’s time to move on to the next step – installation. Before you get started, take notice of whether or not your thermometer offers several installation options. For example, with the POPETPOP LCD Digital Aquarium Thermometer, you can either clip it on to your tank or attach it via the suction cups. Other thermometers, however, like the Qguai Aquarium Thermometer, have a sticky back that can be used to attach to your aquarium. Then there are some like the FREESEA Aquarium Heater requires you to submerge all or part of the device in order to get a proper reading. No matter what type of thermometer you’ve chosen, most are pretty easy to install.
Once again, it is most important to take into consideration the type of animal you are caring for. Tropical fish, for example, require their water temperature to be higher, which means you may want to purchase a heater/thermometer combination, much like the FREESEA Aquarium Heater. However, if your concern is making sure you stay within your budget, consider purchasing thermometers that come with more than one, so you’ll always have a replacement for the same price as one.
If you’re feeling overwhelmed by all the options, don’t be. We’ve narrowed down our list to consist of the top three thermometers out there. In terms of getting the most out of your money, we recommend the VIVOSUN 4-Pack LCD Digital Aquarium Thermometer. At just $11 for a pack of four, it’s a wonder they haven’t sold out yet. You might want to hurry before they do! Our premium pick goes to the Inkbird C929A. For starters, we love that you can control the thermometer using an app on your phone. The dual probes also come in handy as one can serve as a backup if one ever breaks. Last but not least, our Editor’s Choice goes to the JCreate Aquarium Thermometer. We believe this is the best aquarium thermometer for more than one reason. Aside from being accurate and easy to apply, it’s also virtually weightless and doesn’t require any annoying cables. To top it all off, it’s just under $14, so it won’t break your bank.