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Tetra Whisper Internal Power Filter by Tetra

  • $17.99
  • Save $8SALE (44%)
SKU: WL25846
UPC: 046798780564
MPN: AQ-78056
  • $31.99
  • Save $15SALE (46%)
SKU: WL25816
UPC: 046798258162
MPN: 25816
  • $42.99
  • Save $21SALE (48%)
SKU: WL25817
UPC: 046798258179
MPN: 25817
  • $52.99
  • Save $25SALE (48%)
In Stock - FREE shipping over $75
SKU: WL25818
UPC: 046798258186
MPN: 25818

Tetra Whisper Internal Power Filter Description

Tetra Whisper In-Tank Power Filters provide the ultimate in convenience and quiet. These filters mount on the inside of the aquarium, rather than hanging from the outside - making it possible to place the tank flush against a wall.

  • Motor is under the water for extremely little noise
  • Functions in as little as 2 inches of water
  • Includes one pre-assembled Whisper Bio-Bag filter cartridge

In-Tank Filters are unusually quiet, since the motor is under the water. Offering the same quality and performance as an external filter, the Whisper In-Tank Filter will function in as little as 2 inches of water - making it ideal for turtle tanks, or for creating a waterfall inside the tank.

Whisper In-Tank filters adjust easily to high or low water levels with mounting suction cups and/or clip. Each filter includes one pre-assembled Whisper Bio-Bag filter cartridge and mounting clip.


  • 4i: Aquariums up to 4 Gallons, 24 GPH, Use S Cartridge.
  • 10i: Aquariums up to 10 Gallons, 90 GPH, Medium Bio-Bag. 4.2"L x 4"W x 8"H
  • 20i: Aquariums up to 20 Gallons, 125 GPH, Large Bio-Bag. 4.9"L x 5.4"W x 10.2"H
  • 40i: Aquariums up to 40 Gallons, 170 GPH, Large Bio-Bag. 5.1"L x 5.9"W x 10.5"H

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Tetra Whisper Internal Power Filter Customer Reviews

Brenda, Jacksonville NC on 2017/08/25
Tetra fish tank filters

It is the only brand of filter I use and will ever use very dependable

Laura, Bloomington IL on 2017/04/02
Only Filter Ill Buy

I have one 40i and another (green one) that's similar but not as good. When the green one died, I made the mistake of buying a Cascade. Never again will I buy anything but a 40i. I had no idea how great this filter was until I tried something else. I spent more money on a filter that I do not like. Lesson learned. Only Tetra 40i's from now on!

Carol, Prairie Du Chien WI on 2012/05/08
Excellent product.

These are the only internal aquarium filters I will ever use. They keep the water crystal clear. If a power outage occurs, they will restart in very little water. I almost had a house fire because another filter would not restart and the motor overheated. They come in three sizes. Perfect for any aquariust.

Joe English, Pikeville TN on 2012/01/10
Best Yet.

I have 6 aquariums. I have used the Marineland Bio wheel filters. They are expensive to replace cartridges and always having to take apart for cleaning and repairs. I have replaced some with Tetra 40I and love them. They are super quiet; a fraction of the cost for cartridges (I make my own). I have two in a 55 gal. And two in a 45 gal. When I can afford them I am going to order 4 more for other tanks. The best inexpensive filter yet.

Theresa , Tracy CA on 2010/11/08

This works perfect for my 2 turtles I went overboard but it keeps it clean! And smells good!

Kim, Clinton Twp MI on 2010/10/13
Great Products!

I have been using tetra Whisper filters and bio-bags for years. I have an aquarium and I have a turtle tank with four turtles. I use 3 intank whisper filters in the turtle tank and they work great!

Kelly, Glen Burnie MD on 2010/06/24


Stacy, Hammond IN on 2010/04/20
tetra pf-40i filter is awesome

We bought the pf-40i and a pf-20i and for our 55 gallon tank. They are working great and are so... quiet. They are also great because they take up no space on the outside of tank.

Jan, Fayetteville OH on 2009/10/14
Good, inexpensive filter

I purchased this in tank filter after my regular filter leaked on my hardwood floor twice. Very quiet and seems to do a good job. Excellent filter for the price.

Mike, Poseyville IN on 2008/06/20

This is a great filter we use them on all our turtle tanks!

Eric, Quincy IL on 2007/11/23
One great filter

I have two Tetra Whisper 40i submersable filters and I love them. I have a 55gln aquarium with lush plant life and many beautiful fish and thanks to the Whisper 40i I am gettig better results in this aquarium than I have with any other filter product.I definately recomend this submersable filter for anyone that wants great results for their aquarium and for a long life for their loveable fish buddies.You have to have one...or two. Heck I'm ordering another one for my 29gln aquarium today.:)

Mary, Sandy Creek NY on 2007/07/27
Excellent filtration!

I purchased In-tank filter 101 and 401!They prove excellent filtration for two tanks, one a 10 gallon and one 45 gallon which each house a turtle. Turtles put out a lot of waste and these filters work the BEST I have ever used. The ease in which I can change the filters is wonderful!

Christian Traylor, Columbia SC on 2007/05/06
Incredibly reliable

I left my bio-wheel filter in South Carolina when I came home for the summer, and needed a cheap filter. I bought this one, and discovered that it is just as effective as my biowheel. There is plenty of space for beneficial bacteria to grow, and it clears the water out BETTER than my Penguin filter. I was very suprised. I would recommend this to anyone. When I get my other filter back, I'm going to use both of them to keep the tank clean and extra healthy. An amazing and cheap filter - great for all fish.

Marco, La Puente CA on 2007/04/16
great buy

I love this thing all I had to do is open the box put the cartridge in then plug it in. It was that easy it cleans great and quietly too. This filter is great for the money :)