Heaters · Adjustable, electronic
Fluval E300
Manufacturer-rated for aquariums up to 100 US gal.
300 W submersible heater with digital temperature display, dual sensors, and fish guard.
Consider: The 14-inch body can exclude shallow tanks. Compare that height with the mounting position and water depth in the instructions before ordering.
US version, item A774. Check what’s in the box before you buy.
Tank size Fluval rates it for
Up to 100 US gal
Choose your tank to see where it falls.
Check it against your tank →Specifications that affect fit
- Manufacturer capacity
- Up to 100 US gal
- Power
- 300 W
- Supply voltage
- 120 V / 60 Hz
- Dimensions
- 2 × 1.25 × 14 in (L × W × H)
To see what it costs to run, enter the watts on its label and your daily hours in the electricity cost calculator.
Before choosing this model
- Size for tank volume and temperature rise above room.
- Verify actual water temperature independently.
Our buying guides size it for these tanks:
29 gallon40 gallon55 gallon75 gallon
A heater rated for your tank can still fall short in a cold room: see how to size one.
Check it against your tank → Something not working? See the troubleshooting guide.
Included items & upkeep
- heater
- fish guard
- mounting bracket
Plan for the routine work
- Unplug and cool before removal.
- Inspect the mount and exterior for deposits.
To budget for replacement media and supplies, use the first-year cost calculator. For how often and how to clean it, follow the maker’s manual.