Marina Floating Thermometer with Suction Cup for Aquariums

$3.99 (-11%) Chewy Price
$4.48 List Price

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About This Item

Details

  • Perfect for freshwater or saltwater use
  • Accurate and easy to read, provides readings in Centigrade and Fahrenheit
  • Safety zone indicator for most tropical fish
  • Helps protect your fish from unsafe temperatures
  • Designed to float in the water in a vertical position or includes an optional suction cup

Instructions

Learn More About Marina From Our Team of Experts

Questions & Answers

9 Customer Questions


What is the fluid inside this THERMOMETER? Just realize it broke! getting ready to drain tank freaking out my bala sharks might die. If anyone has any helpful advice about this thermostat please. It was in the back of tank was using as a back up incase digital went out. Sharks are Not eating today.

Answer by ChewyApr 19, 2018
The fluid inside the thermometer is a red dye mixed alcohol but the amount used should not be enough to cause harm to your fish.

Whats on the bottom of this?? And when should i replace this if i need to do so?

Answer by ChewyJan 11, 2019
In the very bottom of the thermometer, there is liquid alcohol and steel shot. If there is any damage to the thermometer, it should be disposed of, along with a water change and replacing the substrate, if pieces have broken apart into the aquarium.

Can it be 100% submerged under water? Or will it float away?

Answer by ChewyMar 12, 2022
The Marina Floating Thermometer works in both freshwater and saltwater tanks and is designed to float in a vertical position. A suction cup is included if you prefer to attach it to the aquarium wall.

What are the little metal looking balls at the bottom of the thermometer? Are they toxic if it breaks and get in the water?

Answer by ChewyJun 18, 2018
If an aquarium thermometer breaks, although it is not composed of any inherently toxic materials, any pieces should be removed to ensure the environment is not damaged over time. This includes the small balls, which will rust and could be a potential problem for the environment if left for an extended period of time.

4.1
Rated 4.1 out of 5 stars
256 Ratings

170 Customer Reviews



Rated 5 out of 5 stars
By David on Jan 30, 2026

It's an old school thermometer that is cheap and accurate.

The downside to these types of thermometers is that they are difficult to read. The green highlighted area between 70-80 degrees gives you an idea of where you are

The downside to these types of thermometers is that they are difficult to read. The green highlighted area between 70-80 degrees gives you an idea of where you are with a quick glance since most aquariums are going to be within that temperature range. I personally have these or similar thermometers in all my tanks because the digital thermometers are not as accurate and the batteries die in them. The upside of course being that they are much easier to read. This is why I say the green area of the thermometer helps with giving an idea of your aquariums temp at a quick glance.


Rated 4 out of 5 stars
By kara on Dec 19, 2025

Small thermometer for small aquariums

Easy to set up in the aquarium, and easy to read once placed. Small size perfect for smaller aquariums. Only 4 stars as I only had this thermometer for only 7 months

Easy to set up in the aquarium, and easy to read once placed. Small size perfect for smaller aquariums. Only 4 stars as I only had this thermometer for only 7 months when the glue that held the center glass tube and measurement paper failed and they both fell, making it no longer useable. Hopefully that was just an unusual faulty product & this one will last much longer.


Rated 3 out of 5 stars
By Scherry on Oct 15, 2025

This doesn't work for me

This doesn't work for me due to bad eyesight. It will probably be great for someone who has better eyes. The print is super small and I can't even see it with a

This doesn't work for me due to bad eyesight. It will probably be great for someone who has better eyes. The print is super small and I can't even see it with a magnifying glass. I gave it away.


Rated 5 out of 5 stars
By Alvin on Dec 13, 2025

Thermometer

I have used this brand of Thermometer for years and they are good ones.

I have used this brand of Thermometer for years and they are good ones.


Rated 5 out of 5 stars
By Scott on Aug 31, 2025

Cheap effective thermometer

Highly recommend a thermometer like this in lieu of relying on the tape thermometer that comes with some kits. They are useless.

Highly recommend a thermometer like this in lieu of relying on the tape thermometer that comes with some kits. They are useless.


Rated 1 out of 5 stars
By Lea on Feb 28, 2025

Needs better packaging

The thing arrived shattered at the bottom. Very delicate glass from what I can tell, so glad it didn't go into my tank and then break, I imagine it wouldn't hold

The thing arrived shattered at the bottom. Very delicate glass from what I can tell, so glad it didn't go into my tank and then break, I imagine it wouldn't hold up well in there either.


Rated 5 out of 5 stars
By Cheryl on Oct 23, 2025

Cheap

Reliable and durable

Reliable and durable


Rated 1 out of 5 stars
By ft25 on Jan 1, 2025

Tiny text--Numbers don't line up with lines

The graduation lines do not line up with the numbers, for instance the number is in the middle of two bold lines, which are top and bottom. With the text and lines

The graduation lines do not line up with the numbers, for instance the number is in the middle of two bold lines, which are top and bottom. With the text and lines being so tiny, the thermometer is unreadable. Plus, the suction cup has been out of the package outgassing for a week and still stinks like chemicals. Not even worth it if free.


Rated 2 out of 5 stars
By Budbrian on Jan 1, 2025

Ok thermometer

It’s ok very hard to read probably need a magnifying glass to read

It’s ok very hard to read probably need a magnifying glass to read


Rated 5 out of 5 stars
By Jennifer on Feb 15, 2025

Great products, fast shipping

Adjustable and submersible heater is perfect

Adjustable and submersible heater is perfect