Buy new:
To see product details, add this item to your cart.
FREE Returns
Ships from: Amazon.com
Sold by: Amazon.com
To see product details, add this item to your cart. You can always remove it later.
FREE Returns
To see product details, add this item to your cart. You can always remove it later.
FREE Returns
Added to

Sorry, there was a problem.

There was an error retrieving your Wish Lists. Please try again.

Sorry, there was a problem.

List unavailable.

Fluval M50 Ultra-Slim Submersible Aquarium Heater – 50W Underwater Heater for Aquariums up to 15 Gal.

4.6 4.6 out of 5 stars 4,846 ratings

To see product details, add this item to your cart. You can always remove it later.
FREE Returns
Available at a lower price from other sellers that may not offer free Prime shipping.
M50

Purchase options and add-ons

Brand Fluval
Target Species Fish
Material Ceramic, Borosilicate Glass
Product Dimensions 1.8"L x 4.8"W x 14.8"H
Item Weight 9.86 ounces
Style M50
Included Components Fluval M50 Submersible Glass Aquarium Heater (50 watts)

About this item

  • Modern Aesthetic: M-Series heaters combine modern aesthetics with reliable Italian construction. Employing an ultra-slim profile, these heaters are a welcome departure from traditional, bulkier designs.
  • Reflective Design: This heater is encompassed in a heat-and-shock resistant reflective Borosilicate glass tube, which allows it to reflect the surrounding aquarium colors, allowing it to blend in with the environment and enhance overall aesthetics.
  • Temperature Control: Computer-calibrated thermostat has an easy-to-adjust temperature control dial and an on/off blue indicator light to display when it’s in use.
  • Slim Profile: Ultra slim design allows for easy installation in your aquarium tank.
  • Recommended Size: M50 underwater heater is ideal for freshwater and saltwater aquariums up to 15 gallons. Each M-Series heater comes with a 3-year limited warranty.

Customer ratings by feature

Suction power
4.3 4.3
Temperature Control
4.0 4.0
Accuracy
3.8 3.8

Frequently bought together

$22.58
Get it as soon as Tuesday, Apr 2
In Stock
Ships from and sold by Amazon.com.
+
Total price:
To see our price, add these items to your cart.
Details
Added to Cart
These items are shipped from and sold by different sellers.
Choose items to buy together.

From the manufacturer

Fluval M Submersible Heater

The M-Series submersible heater range provides exceptional performance, unsurpassed reliability and exclusive mirror technology to blend in with its surroundings.

  • 50-Watt heater designed for aquariums up to 15 gallons
  • Durable, mirrored finish seamlessly blends heater into surroundings by reflecting colors of the aquarium
  • Computer-calibrated thermostat
  • Easy-to-adjust temperature control dial
  • Sleek and compact design
  • For use in freshwater and saltwater aquariums

Product guides and documents

Product details

  • Is Discontinued By Manufacturer ‏ : ‎ No
  • Product Dimensions ‏ : ‎ 1.8 x 4.8 x 14.8 inches; 9.86 ounces
  • Manufacturer recommended age ‏ : ‎ 1 month and up
  • Item model number ‏ : ‎ A781
  • Date First Available ‏ : ‎ August 19, 2004
  • Manufacturer ‏ : ‎ Rolf C. Hagen (USA) Corp.
  • ASIN ‏ : ‎ B0027VMPXA
  • Country of Origin ‏ : ‎ Italy
  • Customer Reviews:
    4.6 4.6 out of 5 stars 4,846 ratings

Looking for specific info?

Product Description

The Fluval M Submersible Aquarium Heater’s quality European manufacturing utilizes superior components and construction. The Fluval M50 Submersible Heater is ideal for use in freshwater and marine aquariums up to 15 gallons and has a temperature range of 66-86 degrees Fahrenheit. This sleek, compact heater can be trusted for exceptional performance and unsurpassed reliability. Unique only to the Fluval "M" series the reflective technology equipped in the Fluval M Submersible Aquarium Heaters helps maintain the aquariums' natural look as the heater reflects the colors of the surroundings.

Fluval first broke onto the aquatic scene in 1975 by introducing the world’s first 3-stage filter with synchronous motor technology – a landmark breakthrough that is still applied in the industry today. Since then, Fluval has built a legacy around this pioneering spirit, relentlessly adapting in a changing world to launch innovative aquarium products that remain at the forefront of technology, and which set the bar in quality, style and functionality. Above and beyond its manufacturing role, Fluval prides itself on its charitable and educational efforts that give back to the fishkeeping community, whether it means helping to fund the protection of wild coral reefs or jumping on a plane to document endangered fish species halfway around the world. Fluval’s mission is not just about building products that mimic the natural world, but inspiring aquarists of all skill levels to enjoy and respect the hobby for generations to come.

Important information

Directions

Follow individual packaging instructions

Customer reviews

4.6 out of 5 stars
4.6 out of 5
4,846 global ratings

Customers say

Customers like the quality, appearance and value of the pet toy. For example, they mention it functions well, it's reliable and accurate. Some appreciate the minimalistic design and the reflective tube. That said, most are happy with ease of installation. That being said, opinions are mixed on accuracy, submersible, and fit.

AI-generated from the text of customer reviews

341 customers mention254 positive87 negative

Customers like the quality of the pet toy. They say it functions well, is reliable, and lasts longer than some other heaters. Some mention that it works perfectly with their Fluval flex aquarium.

"...Very sturdy and made very well. I would definitely buy again!" Read more

"I have several M series heaters. They have all been accurate and reliable...." Read more

"...: These are nicely designed, sturdy heaters with strong borosilicate glass, quality interior components, and sleek contemporary..." Read more

"...any of my fish when it busted, it just ended up cracking, and the bottom fell off...." Read more

309 customers mention222 positive87 negative

Customers like the temperature adjustment of the pet toy. They mention it's amazing at holding constant temperature, keeps water warm, and has accurate temperature control. Some say the heater actually heated the water to what they set it at, and that it heats the water quickly. They also appreciate the simple design and the easy-to-adjust temperature dial on the top.

"I have this heater in my 30 gallon aquarium and it does a great job and keeping temp...." Read more

"Keeps the tank at a steady temp and doesn’t fluctuate much" Read more

"...The only problem I ran into, eventually I could not read the temperature gauge for the dial anymore because it came off or become covered in algae...." Read more

"...The thermostat is of high quality, with less temperature variation than most, but the poor calibration made that irrelevant...." Read more

88 customers mention80 positive8 negative

Customers like the appearance of the pet toy. For example, they mention it has a minimalistic design, is sturdy, and has borosilicate glass. Some appreciate the sleek, camouflaged glass look that doesn't take away from the aquarium. That said, some complain about the temperature setting dial.

"...They have all been accurate and reliable. Big and shiny and not for aquascapers, but great for people who just keep fish." Read more

"...: These are nicely designed, sturdy heaters with strong borosilicate glass, quality interior components, and sleek contemporary..." Read more

"Looks nice and is fairly unobtrusive in my tank...." Read more

"...I like the simple design and it is easy to adjust the temp, just turn the dial on the top...." Read more

54 customers mention44 positive10 negative

Customers like the value of the pet toy. They say it's cheap and reliable, and an economical way to heat a tank.

"...It’s also not very expensive for the sheer quality you will receive. The mounting is especially solid and sleek as well...." Read more

"...Otherwise a great heater at a good price." Read more

"...I recommend this one. Cheap and reliable. I have one for each of my tanks. No more problems or worries. [..." Read more

"Reasonably priced and Fluval quality has never let me down before. 6 ft cord is a plus and it seems to be accurate within 2 degrees" Read more

38 customers mention29 positive9 negative

Customers find the installation of the pet toy to be easy. They say it's extremely easy to set the temperature, plug and play with no issues, and use with the temperature control on the top. Customers also mention that the temperature is easy to read and the control is conveniently located at the top of the heater.

"...But like all heaters they do go out after some time. I like how easy it is to set but wish it had a digital display showing the temp instead but that..." Read more

"...Tube shows where minimal water line is near the top. Super easy decision, seriously, spend more time enjoying the hobby. Hope this is helpful." Read more

"...Not exactly accurate but it's very easy to use and is working well so far. No complaints other than the slight inaccuracies." Read more

"...for a 55g. At highest setting, keeps water temp at 78F. So, a little underwhelming, but works fine, keeps temps right at set temps." Read more

48 customers mention17 positive31 negative

Customers are mixed about the submersible. Some mention that it's an absolute plus, while others say that it is not fully submersable.

"...I never realized that the heater was not fully submersible, just to the two water lines...my original heater I kept just about dully submerged in my..." Read more

"...But it is fully submergible. I know it says didfferently...." Read more

"...Finally, I wanted to dispel the myth that this heater is not fully submersible...." Read more

"...There is a misconception on the internet that the heater isn't fully submersible. The line is there due to regulations in certain countries...." Read more

46 customers mention25 positive21 negative

Customers are mixed about the accuracy of the pet toy. Some mention that the accuracy is perfect, perfectly calibrated, and consistent. However, others say that the dial is not accurate, making it difficult to estimate an exact setting.

"I have several M series heaters. They have all been accurate and reliable...." Read more

"...high quality, with less temperature variation than most, but the poor calibration made that irrelevant...." Read more

"This unit is perfectly calibrated right out of the box, keeps a steady temperature without constantly cycling on and off...." Read more

"...tank set at 79 and thermometer reads 82, I set it to 75 it reads at 80 very inaccurate and the size of it is pretty long the aquatop is more small..." Read more

43 customers mention15 positive28 negative

Customers are mixed about the fit of the pet toy. Some mention that it fits perfect in their 30 gallon tank, while others say that it's too long and tall for the 5 Gallon Fluval Nano tank.

"...Tried sliding the holder further down but the holdef fits too loosely and the heater is top heavy, so I added another suction cup at the bottom of..." Read more

"Added to our Fluval Flex AIO tanks, fits perfect in the rear compartment so it stays hidden...." Read more

"...a 5 gallon tank and it is longer than my tank is tall so it has to lay diagonal to fit. Hopefully it works just as well...." Read more

"...They have been the best and longest lasting I've tried. This 50 is a bit long for it's intended use 5-10 gallons. But it is fully submergible...." Read more

Heater works perfectly
5 Stars
Heater works perfectly
Highly recommended, Prompt Shipment and Precise Item received.
Thank you for your feedback
Sorry, there was an error
Sorry we couldn't load the review

Top reviews from the United States

Reviewed in the United States on February 23, 2024
Reviewed in the United States on February 18, 2024
Reviewed in the United States on March 1, 2024
Reviewed in the United States on November 3, 2017
Customer image
Liz
5.0 out of 5 stars Great, long lasting heater.
Reviewed in the United States on November 3, 2017
I used Amazon to purchase my second Fluval 100w submersible heater, because it was a better price Tha PetSmart.
My first one, I purchased at a local pet store about 6 years ago, and didn't fail me once. My original heater was used everyday, not once was it turned off, except with water changes and other maintenence. It kept my tropical fish warm and happy year round at 72°.
I never realized that the heater was not fully submersible, just to the two water lines...my original heater I kept just about dully submerged in my tank, but never had any issues in doing this. The only problem I ran into, eventually I could not read the temperature gauge for the dial anymore because it came off or become covered in algae. My new one I will be sure not to fully submerge it, but it will still be over the water line, otherwise it wouldn't fit under the hood.
I could have replaced the heater sooner, and wish I had...the week before my old one broke, I had put it down on the list of things to get. Pretty lucky that the heater didn't hurt any of my fish when it busted, it just ended up cracking, and the bottom fell off. This doesn't falter decision on my rating though, the heater lasted longer in my tank than any other I have used in the past, and I have kept aquariums for about 15 years now.
Images in this review
Customer image
Customer image
8 people found this helpful
Report
Reviewed in the United States on October 17, 2011
9 people found this helpful
Report
Reviewed in the United States on December 1, 2023
4 people found this helpful
Report
Reviewed in the United States on February 21, 2024
Reviewed in the United States on February 19, 2024

Top reviews from other countries

Translate all reviews to English
Jean-Francois Daneau
5.0 out of 5 stars Should of been boxed
Reviewed in Canada on February 18, 2024
RaC
5.0 out of 5 stars Ha salido muy bueno.
Reviewed in Mexico on May 1, 2023
One person found this helpful
Report
Dario
5.0 out of 5 stars Bom aquecedor aquário
Reviewed in Spain on May 13, 2023
UnGatekeeper
3.0 out of 5 stars Not transparent, too long
Reviewed in Sweden on January 30, 2023
Yssak
5.0 out of 5 stars Magnifique et solide
Reviewed in France on October 13, 2022