Fluval M 100Watt Submersible Fish Heater

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$32.99 (-8%) Chewy Price
$35.99 List Price
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About This Item

Details

  • Quality heater made in Europe with quality components.
  • Sleek and compact design.
  • Submersible heater delivers excellent performance and reliability.
  • Mirror technology reflects the colors of the aquarium to enhance its appearance.
  • For fresh and saltwater tanks.

Instructions

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Reviews
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4.6
Rated 4.6 out of 5 stars
25 Ratings
Terms & Conditions

11 Customer Reviews

Rated 5 out of 5 stars
By Alex on Dec 15, 2025

Fits in IM nuvo 20

It’s a tight fit, but it does just fine. Had no issues getting it dialed to temperature either.

It’s a tight fit, but it does just fine. Had no issues getting it dialed to temperature either.

Rated 5 out of 5 stars
By Thalia on Dec 14, 2025

Nice heater

Perfect for my tank, fishies happy

Perfect for my tank, fishies happy

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

Been using for many years

Very reliable and sleek mirrored finish.

Very reliable and sleek mirrored finish.

Rated 4 out of 5 stars
By McKenzie on May 2, 2025

Quality Heater

Very good heater, stable temp output. My only complaint is that i had to set it to 85F to get around 78F in the tank, and there was no way to calibrate this model

Very good heater, stable temp output. My only complaint is that i had to set it to 85F to get around 78F in the tank, and there was no way to calibrate this model. It has held my tank at a very stable temp

Rated 2 out of 5 stars
By Jen on Mar 4, 2025

Hoped for the best..

This was the second tank heater I bought. I bought this because it was adjustable and knew that 82ish would be 78 degrees, but I could atleast turn it up to what

This was the second tank heater I bought. I bought this because it was adjustable and knew that 82ish would be 78 degrees, but I could atleast turn it up to what I need. But what I didn't know is that after a week of working great, I woke up to a 75 degree tank. I turned it up and the light didn't turn on. It was dead. I up plugged it and waited, plugged back in and its wrong. It must have some sort of turn off and I can't trust that it won't turn off again. It was in the water, submersed.

Rated 3 out of 5 stars
By Lena on Jan 9, 2025

Not much power

I have this 100w in my 30 gal which should be completely fine. My fish are normally at 78 degrees but even at the heater's maximum temp (which is 82 or 84 I think?),

I have this 100w in my 30 gal which should be completely fine. My fish are normally at 78 degrees but even at the heater's maximum temp (which is 82 or 84 I think?), I can't get track temp above 76. The 2nd floor room it's in is very warm all the time due to our woodstove, so this shouldn't be the problem that it is. Disappointed.

Rated 3 out of 5 stars
By ft25 on Jan 1, 2025

Well made, nice adjustment, but low power

Not a bad heater, though I have 100W in a 20 gal tank which is plenty of heating power, and it can only keep the tank about 5 degrees cooler than the set point

Not a bad heater, though I have 100W in a 20 gal tank which is plenty of heating power, and it can only keep the tank about 5 degrees cooler than the set point. That is, I set at 82 and it maintains 77. I do like the tactile click of the adjustment knob which is 1 degree at a time, which is handy.

Rated 5 out of 5 stars
By Shawna on Oct 17, 2024

Great heaters

Anytime I don't buy a fluval M Series heater I regret it. These have been the most reliable heaters I have purchased. They out last any other brand. I am a fish

Anytime I don't buy a fluval M Series heater I regret it. These have been the most reliable heaters I have purchased. They out last any other brand. I am a fish breeder and seller so I have many of these heaters in my tanks.

Rated 5 out of 5 stars
By Renee on Dec 17, 2024
Top 250 Contributor

I like it

My little cheesy one in my Beta 5 gallon was getting too hot so I had to replace it with this. I like it.

My little cheesy one in my Beta 5 gallon was getting too hot so I had to replace it with this. I like it.

Rated 4 out of 5 stars
By Steve on Jan 26, 2025

Stable temperature

Replaced heater in my 20 gallon tank, keeps temperature stable.

Replaced heater in my 20 gallon tank, keeps temperature stable.