Aquarium Thermometer

Have you thought about how important the Aquarium Thermometer is to your tropical fish tank setup?

Many freshwater tropical fish keepers make the mistake of purchasing a cheap heater, setting the temperature to 78°F, and going on about their business. Many do not think about the need for an aquarium thermometer.

Purchasing a reliable fish tank thermometer is very important so that you know exactly the temperature in the water. One cannot depend on the good ole “put the finger in the water” to see if it’s cold or hot method. 

Below I will discuss the different types of tropical fish tank thermometers available and recommend some that I use in my fish room.


External Sticker Thermometers

This is the most popular thermometer in the fish-keeping hobby. The stick on thermometer has a sticky back and is placed on the outside of the fish tank directly on the glass or acrylic.

When I say these are the most popular, I am not saying that they are the best. They are pretty accurate and usually within 1 degree plus or minus from the true temperature of the water inside the aquarium

Digital Thermometer

This type of fish tank thermometer is the one I prefer to use in my tropical fish tanks. This digital device sits on the outside of your fish tank by either a suction cup or Velcro. The temperature is measured by a probe that is attached by a suction cup on the inside of your aquarium under the water.

I truly believe that you get a more accurate temperature measurement from this device because you are taking the temperature directly from the water inside the tank instead of the temperature on the outside of the glass.

Digital thermometers use batteries and can be mounted and moved when and where you desire. Some models include a built in light to help you see the reading in a dark room. Other models include alarms that will alert you when the tank water reaches temperatures too high or too low. There are models available that measure the room temperature and include a clock also.

Floating Glass Thermometer

The last type of thermometer I would like to share with you is the floating glass styles. These are simply glass tubes filled with mercury and most have a suction cup attached that allow you to attach to the inside of your aquarium.

This type will be in the water of your aquarium and does a good job of reading the temperature accurately. The downside to this style is that it is a bit hard to read while floating around inside the fish tank.

I use this style when transferring fish. I will use this as my travel thermometer. It will do the job but it is a bit harder to read compared to the digital thermometers.


Fish Tips

I highly recommend you use more than one of the above mentioned on your home aquarium. I use a stick on and digital thermometer on each fish tank in my house. This way I have a backup if one were to fail.

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