Fluval M Series Heater

Written by Kmuda. Posted in Heaters



  • European-made aquarium heater boasts quality performance
  • Shock-resistant glass heater mirrors aquarium surroundings
  • Maintain proper water temperature AND aquarium aesthetics

Ultra modern design meets reliable European aquarium heater technology. The Fluval M Series Submersible Heater is a welcomed departure from bulky unsightly heaters. This beautifully-designed submersible aquarium heater features a reflective shock-resistant borosilicate glass tube that houses superior components including a computer calibrated thermostat-all backed by a 16 point quality assurance program. Easy-to-adjust temperature control dial allows temperature settings between 66-86° Fahrenheit. Elegant, slim-profile heater occupies less space and unique mirror-like surface reflects surrounding colors to blend harmoniously into the aquarium environment. The Fluval M Series Submersible Heater is safe for fresh and saltwater aquariums. Submersible to water line on heater.

Model Length Max. Aquarium Size Max. Depth
50W 11" 15 gallons 8"
100W 11" 30 gallons 8"
150W 13" 45 gallons 10"
200W 13" 65 gallons 10"
300W 15" 80 gallons 12"

General Information

Fluval M Series premium heaters are quality manufactured in Europe using superior components and construction. These include the heat and shock-resistant borosilicate reflective glass tube, heat-resistant techno-polymer conductor harness, high temperature-resistant heating element, silver-nickel contact points, machine assembled thermostatic blade, computer calibrated thermostat and 16 point quality assurance program. Fluval heaters can be trusted for exceptional performance and unsurpassed reliability.

Unique only to the Fluval M Series, the reflective technology helps maintain the aquariums natural look as the heater reflects the color of the surroundings.


  • Easy to adjust temperature dial
  • Exclusive slim profile tube
  • Reflective technology-Unique to Fluval, the reflective technology maintains the aquariums natural look as the heater reflects the colors of the surroundings
  • Shock-resistant borosilicate glass
  • Cool blue ON/OFF Indicator lamp
  • High-density ceramic Heat Sink extends heating efficiency
  • Exclusive sealing system protects against water penetration
  • High temperature silver-nickel pointed thermostat for extended accuracy and service life
  • Long life suctions cups


Fluval M Heater Review

by Kmuda


Finding a good heater is becoming more and more difficult these days and having historically had such good luck with Fluval Tronic Heaters, I decided to try Fluval's latest heater, the Fluval M.

It was a mistake.

Ignore the "Reflective Technology" marketing hype. It's a bad simulation of a mirror. It does not hide in the background at all. But that is not the real problem. My heater only lasted about 3 months in 55 gallon tank containing nothing but a Pleco. It will still heat the water, but cracks are clearly visible in the glass, so it has been removed and trashed. A closer inspection identifed water has indeed made it into the heater. A disaster waiting to happen.

Might work great in a tank containing small fish (like guppies and tetras) but this heater cannot be recommended in anything containing fish of anything approaching substantial size. The heater certainly should not be considered for an Oscar Tank (or any large cichlid). You'll also need to apply caution when performing maintenance or cleaning. A decent accidental bump of the heater against the glass may cause breakage.


  • Steady Temperature: While it lasted, it maintained a very steady temp.
  • Appearance: Disregarding the marketing hype, the heater is a sleek looking heater and the blue light (means on) indicator is cool (in the true sense of the word).
  • Easy to Adjust: The temperature knob is very easy to move in small increments, which allows for smooth adjustments of the temperature.


  • The darn thing has cracks in it after 3 months of use, from nothing more than a Pleco.