Whisper 20i In-tank Filter - Up to 20 gal.

SKU: 205736
Manufacturer: Tetra
MPN: AQ-65817

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The super quiet Whisper in tank aquarium or terrarium filter that is ideal for 10-20 gallon tanks. The Whisper in tank filter is easy to conceal inside your aquarium; hide it behind a plant or other decorative object and from the front it is practically invisible. Space-saving design can be flush with the wall and operates in as little as 2 in. of water, making it ideal for low water level environments like amphibian aquariums, terrariums or turtle tanks. Complete 3-stage biological, chemical and mechanical water filtration is provided from the same Whisper Filter Cartridges used in the famous Whisper Power Filter. Whisper Filter Cartridges contain precisely the amount of activated carbon and filter mesh area to provide superior aquarium filtration. UL listed.

For more info on Internal or Submersible Filtration, please see Internal Aquarium Filter Basics.


Includes MediaLarge Bio Bag
Flow Rate125 gph
Power Cord Length6 ft.
Warranty2 year Warranty
UL ListedYes
Max Tank Size20 gal.
Internal Id


Click here to download the instruction manual from Tetra's website.

Ratings & Reviews

5 reviews

20i good & quiet


This is a good filter, and it is Very quiet

Whisper 20i In-tank Filter - Up to 20 gal.


Ths is a excellant filter, my fish tank is crystal clear thanks to Whisper. I'm so glad I purchase it two weeks ago. It is very quite too!

Good filter


It's a little noisy and does an okay job of keeping the tank clean. I would consider buying this again.



It works fine but it can get considerably loud depending on your "lid" to the fish tank. The tank i got came with it and its extremely loud sometimes that I'm unable to sleep from the noise.

super quiet in my tank


I have a 30 gallon. I bought this to use along with an aquaclear. The aquaclear does a grwzt job with bio filtration but it d I ent do a goid job withvthe mechanical filtration. I cant hear it at all. I replaced a Quiet Fl I w tgat was anything but quiet. I live in a very small house and I could hear that filter eve r ywhere, it drove me nuts. So I replaced it with this mechanical filter. My tank is literally 4 feet from my couch and I csnt h ear it at all. Not sure why other reviewers can hear it. Might be that they have very small tanks so the filter is possibly vibrating off more tank or rocis or decorations?? I got my sanity back with a quiet livingroom again. It is clearing up the tank fast too after stirring up the plant dirt a bit after I dud some plant maintenance.