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.
Dimensions
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.
Weight

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.
Temperature range
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.
Cable length
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.
Accuracy
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.