Whisper® Internal Aquarium Power Filters

Product No. 25816
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The Tetra Whisper internal aquarium filter is the ultimate in quiet, convenient 3-stage filtration. The dual-sided mesh of the Bio-Bag® catches debris and fish waste while the activated carbon absorbs odors and discoloration. Biological filtration is provided by the Bio-Scrubber. Bio-Scrubber's anti-clog design provides complete biological filtration with the convenience of less maintenance. Because the Bio-Scrubber has a solid back, water is forced to flow evenly over the bacteria-rich bristles. The filter is submersible.

NOTE: The filter now comes with a clip to hold the filter. If suction cups are needed please contact Consumer Services at 1-800-322-1266.

Whisper 3i - 20 GPH
Whisper 10i - 80 GPH
Whisper 20i - 125 GPH
Whisper 40i - 170 GPH
Whisper® Internal Aquarium Power Filters is rated 3.1 out of 5 by 64.
Rated 2 out of 5 by from no longer works. i have had mine for less than 2 years.it no longer works.yes i cleaned it.yes i removed the perpailer.the motor isnt even making a noise.its like it went out.so ya luckily i got betta or it would be dead.
Date published: 2017-05-19
Rated 1 out of 5 by from Dissapointing My son wanted a turtle so I went out and got the turtle and this filter system. At first it seemed very good. The water was clear but by the second day, the water was murky and remains so. stays murky. It is not filtering like it should. I've seen others turtle owners who use this system and the water stays clear. I don't know what the problem is.
Date published: 2017-05-09
Rated 4 out of 5 by from Suction cups I bought a tetra whisper filter from Walmart last week and as I was installing, I saw that it didn't have suction cups. So I thought that someone must have taken them. Then, I went to Walmart to return it for a new box and there weren't suction cups AGAIN. So I figured it must not have suction cups and so I've been trying to glue on suction cups and my tetra filter keeps tilting over. I looked at the reviews online and theirs came with suction cups. Is this a manufacture fault or walmart?
Date published: 2017-04-26
Rated 2 out of 5 by from Problem Ive replaced my whisper twice within two months. And I came home again to my tank not getting filtered. Dont think ill be buying another tetra whisper.
Date published: 2017-03-10
Rated 1 out of 5 by from Loud and noisy I purchased this a few days ago and since day 1 it has been making a terrible grinding noise! It is extremely irritating since my last Tetra Filter started doing this in just a few months of use. I will be returning it ASAP.
Date published: 2017-02-15
Rated 2 out of 5 by from Works as described. It is quiet as it says. Cannot use the clip provided. Doesn't allow for the hood/light to sit properly on the top of the tank. Using 2nd suction cup instead of the clip, just had to drop level of water a bit more than I like. Instructions were a little vague on how the filter and the scrubber are inserted but I think they are in correctly. Been running for a few hours now and the water is already crossing over the top of the filter cartridge. That shouldn't be happening already especially being new. Other the few problems, it works as described. Why I give it a Fair rating.
Date published: 2017-02-12
Rated 1 out of 5 by from Bad design. There is a basic design flaw in the Whisper 10i. Not all the water pushes to the front and if one is not careful water will run out and over the clip that holds the filter in place. The water runs over the clip and onto the floor. I have 3 of the filters and at one time or another each of them has overflowed over the clip. I will look for a better filter for a small tank.
Date published: 2017-02-10
Rated 1 out of 5 by from Terrible The filter stopped working and I was unaware of it. I came home my house was full of smoke. All of my fish were dead.
Date published: 2017-01-24
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Is the Whisper 10i comparable to the Whisper 25799-25807?

Asked by: KK13
No, it is a little bit larger and more powerful. The 25799-25807 was the original internal filter and rated for up to 5 gallons. BREX
Answered by: BREX
Date published: 2017-06-20

I have the Whisper 40 and am having a nitrate problem...possibly from over cleaning? I was wondering if the bio-scrubber should be "cleaned?" or left alone? Also should you leave the "lip" of the filter "dirty" with slime/algae?

Asked by: Axiomatica
Nitrates are actually cause by under-cleaning not over-cleaning. They are also found in some tap water. They are due to the gravel not being vacuumed often enough and controlled by water changes, and live plants. You definitely would not leave the lip covered in algae. Also, the bio scrubber should be cleaned whenever it gets pretty clogged, but only with an old toothbrush and cool water. Tetra EasyBalance Plus will help to prevent nitrates from continuing to rise, but only water changes and live plants will remove them. BREX
Answered by: BREX
Date published: 2017-06-20

Do you guys recommend running this filter 24/7 or you can give it some breaks here and there??Ii have mine on a 10 gallon tank with 2 kois and one black moor. also the aeration and filtering combo.do you recommend having it at the same time or alternate?

Asked by: datchikonj
It should always be running, 24/7 and considering your tank is severely overstocked (small koi of 2-3 inches require 20 - 30 gallons each, adult koi require 500-1000 gallons per fish) you should definitely have both the filter and an air stone running at all times to keep enough oxygen in the tank. BREX
Answered by: BREX
Date published: 2017-06-16

I've owned a tetra whisper filter I purchased brand new not even 2 months ago and it is so noisy I can't even think straight. Can I please get some help!!

Asked by: JaredTrimm
It would help to know which model you own. However, most noise issues are due to the following, so you may want to check these things: - sand caught in the impeller or motor, always prevent sand from being pulled in by placing the toe of a nylon stocking over the strainer, or filling it with filter floss as sand destroys impellers, remove any sand that gets pulled in immediately - remove the impeller and clean it by soaking it for a few minutes in distilled white vinegar in case of hard water deposits - remove any air stone near the intake tube - if buzzing is the noise, plug the unit into a power strip with surge protection as you may be experiencing voltage issues - water noise can be eliminated by keeping the water level in the tank at the right level - just below the inside lip of the top frame Please call us if you need more help. 1-800-526-0650. BREX
Answered by: BREX
Date published: 2017-06-14

Where would I find the model number for Tetra Whisper Internal Power Filter 3i? 

Asked by: ymmat1684
The model number is 3i. Technical information regarding the filter can be found on the bottom of the pump. BREX
Answered by: BREX
Date published: 2017-06-05

I have a tetra 20i. Bought it today. My 20e had stopped working and wentt to pet smart and she said rhey stoo making thay filter system and recommended this one. I get jome and realize it has a wire in the water. I do not like this. Is it safe

Asked by: Angel Chretien
Thanks for asking! The internal filters were specifically designed for the motor and chord to be completely safe when submersed in water.
Answered by: Tetra Expert
Date published: 2017-06-01

Are the cords really safe in the water. This is got me nervous

Asked by: Angel Chretien
Thanks for asking! Yes, it is completely safe for the chord to go in the water.
Answered by: Tetra Expert
Date published: 2017-06-01

I just bought the tetra whisper 2-10 for my 10 gallon tank and the first thing that worried me was the fact that the cord is in the water. How can that be safe?

Asked by: AngelMisty21
Thanks for asking, AngelMisty21! The motor and cord are made to go in the water. We have a lot of these filters right here in the Tetra office and have had no issues with them.
Answered by: Tetra Expert
Date published: 2017-06-01
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Whisper Internal Filter Instruction Sheet

Whisper 3i In-Tank Filter Instruction Sheet


Aquarium Size

Cartridge Size


up to 10 gallons



up to 20 gallons



up to 40 gallons