Filters · Hang-on-back

Fluval C3

Manufacturer-rated for aquariums up to 50 US gal; published maximum rim thickness is 1 inch.

Five-stage hang-on-back filter with published in-system circulation, wet/dry chamber, and quick-access media.

Consider: The mechanical frame and chemical basket lift out separately. Leave overhead access for both so cleaning does not require moving the filter.

US version, item 14002. Check what’s in the box before you buy.

Rated for a 20 gal tankDrawn to scale on a 20 gallon long (example). Body 4.7 in deep and 6.7 in tall, hung on the back rim; check the gap behind the tank and the lid cut-out.
Drawing of an aquarium filter (not a photo of the Fluval C3)

Tank size Fluval rates it for

Up to 50 US gal

Choose your tank to see where it falls.

Check it against your tank →

Specifications that affect fit

Manufacturer capacity
Up to 50 US gal
Power
5 W
Supply voltage
120 V / 60 Hz
Dimensions
7 × 4.7 × 6.7 in (L × W × H)
Pump output
Not published
Filter circulation
153 GPH
Maximum flow
Not published

To see what it costs to run, enter the watts on its label and your daily hours in the electricity cost calculator.

Pump output, filter circulation and maximum flow are measured in different ways. Your filter will move less water than the box says once media and hoses are in. Measure it with the flow calculator.

Before choosing this model

  • Confirm item 14002 and the C3 size.
  • Measure aquarium rim thickness and overhead access.

Our buying guides size it for these tanks:

20 gallon29 gallon40 gallon

A filter rated for your tank can still be too tall for your cabinet or too strong for small fish: see how to choose one.

Check it against your tank → Something not working? See the troubleshooting guide.

Choose and care for mechanical, biological and chemical media before buying replacement supplies.

Included items & upkeep

  • poly/foam pad
  • activated carbon
  • BIOMAX
  • Bio-Screen pad

Plan for the routine work

  • Unplug before service.
  • Follow the manual for mechanical media, impeller, seal, and replacement-part service.

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.

Manufacturer instructions