Marina Floating Thermometer with Suction Cup for Aquariums

By Marina
Rated 3.8156 out of 5 stars
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Marina Floating Thermometer with Suction Cup for Aquariums slide 1 of 2
$2.99Chewy Price

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About This Item

  • 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
Play Video: Learn More About Marina From Our Team of Experts
Learn More About Marina From Our Team of Experts

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Aquarium TypeFreshwater, SaltwaterFreshwater, SaltwaterFreshwater, Saltwater
Fish TypeTropical Freshwater, Marine FishBetta, Goldfish, Cichlid...Betta, Goldfish, Cichlid...
Capacity (Max)N/A

Questions & Answers

13 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.

Does is have mercury in it?
Answer by ChewyDec 07, 2017
This product doesn't have mercury.

How do I know what the temp is in the fish tank
Answer by ChewyNov 23, 2017
This product determines the temperature inside of your tank. As the temperature around the thermometer's bulb heats up, the liquid rises in the glass tube. When it is hot, the liquid inside the thermometer will expand and rise in the tube. The opposite happens when it is cold.

ReviewsWrite a Review

Rated 3.8156 out of 5 stars
141 Reviews
Would recommend to a friend

141 Customer Reviews

Rated 5 out of 5 stars
By Mowerman on Feb 26, 2022

Good for the Money

An inexpensive thermometer that works. Put the thermometer in my 55 gallon tank, and the thermometer gave an accurate reading based on my heater settings. The only problem is it's a little hard to read, though the Safe Zone, 70°F to 80°F, is well marked in red. I run my tank at 79°F, and the thermometer went right there and stayed. For the price what more could you want? I used the suction cup to hold my heater. This after having another, older floating thermometer in another tank, that always seems to drift to the back of the aquarium, or is turned away from the front. Looks good, works well, for a nice low price.

Rated 5 out of 5 stars
By Mac6 on May 13, 2022

perfect size easy to read

It’s a perfect size for my 3 gallon tank, easy to read. Love that it’s has the green lines to show where the temp should be!

Rated 1 out of 5 stars
By cherryirises on Apr 9, 2022

Inaccurate and tiny

The reading is incorrect when compared with other thermometers and it's so tiny I can hardly read it even with my glasses.

Rated 5 out of 5 stars
By sofia on Apr 27, 2022


i’ve had it for a while now and it’s stays perfectly and always reads the same temp as my heater.

Rated 5 out of 5 stars
By Luna on Dec 2, 2021

Works perfectly !

I will admit, The reviews had me scared. But this is totally worth it. As someone who doesn’t have a heater in their tank but uses natural sunlight ( snail tank ), this is awesome ! The strip ones that go on the outside of the tank are never accurate and have scared me before with an accurate measurements. It’s nice to finally have a thermometer that works. I feel like the reason why this gets bad reviews is because it takes a while to adjust to fluctuations. But that’s normal for a lot of thermometers. If you have very frequent fluctuations, I wouldn’t get this, but if you have a room temperature tank or a heated tank, I would highly recommend this !

Rated 4 out of 5 stars
By Sarah on Feb 16, 2022

The thermometer is fine but...

It was shipped all by itself in a box meant for 100x as many thermometers. My 2 year old made the box into a car, so I guess it worked out?

Rated 3 out of 5 stars
By Jill on Apr 7, 2022

Aquarium heater

This heater is ok but difficult to read if you are much over 40.

Rated 5 out of 5 stars
By Jack on Feb 5, 2022

Double check

I use a basic, reliable thermometer to double check the digital ones. This one works great!

Rated 5 out of 5 stars
By NikNola on Nov 15, 2021

The Best***

These little thermometers are reliable, unlike electronic ones or stick to glass ones. I’ve used all of these & always come back to the floating thermometers. Always rely on Chewy for pet products. They are The Best too!

Rated 4 out of 5 stars
By Lily on Nov 21, 2021

Dose the job

It’s kinda hard to read but it sticks to the tank well and it’s pretty small doesn’t take to much space and doesn’t bother the snails