Fluval FX6

Last updated: November 9, 2026

Fluval FX6

The flow king for very large tanks, at the lowest cost per rated gallon. Many owners pair it with a second filter on tanks near its rating.

  • Up to 400 galTank size
  • 925 gal/hFlow
  • 5.9 LMedia
  • 43 WPower
Check price at Amazon$406.99

Price checked November 9, 2026. As an Amazon Associate we earn from qualifying purchases.

Pros
  • 925 gal/h of flow for tanks up to 400 gallons
  • Lowest price per rated gallon of the big filters
  • Water-change valve and self-starting pump
Cons
  • 5.9 L of media is little for a 400 gallon rating
  • Large footprint, 15.75 in square

The Fluval FX Series family

Every Fluval FX Series model we rank, smallest first. Ratings compare each against its own tank size.

ModelTank sizeRatingPrice
Fluval FX2Up to 175 gal3.2/5$296.99
Fluval FX4Up to 250 gal3.4/5$337.99
Fluval FX6 (this one)Up to 400 gal3.4/5$406.99

How it scores

The rating comes from 6 measured or published factors, each scored 0-100 against fixed reference points for its tank size. How we rank explains each one.

Specifications

Model numberA219
Capacity
Rated aquariumUp to 400 gal
Pump output925 gal/h
Filter circulation563 gal/h
Turnover2.3x per hour
Max head height10.8 ft
Media
Media volume5.9 L
Canister volume20 L
Features
PrimerYes
Shutoff valvesYes
Built-in UVNo
Built-in heaterNo
Water-change valveYes
Power and build
Power draw43 W
Warranty3 years

Alternatives in this tank size

Fluval FX4

A powerful, efficient filter for big tanks, with a handy water-change valve. Treat the 250 gallon rating as generous and size by media need.

Amazon $337.99
$337.99
Up to 250 gal700 gal/h3.9 L

Compare

Compare the Fluval FX6 with any other aquarium canister filter →

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