Aquarium Filter Floss: Is It Necessary? (2024 Guide)

Planted Aquascape
Planted Aquascape
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: June 11, 2024
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The appeal of filter floss differs among aquarium enthusiasts, sparking numerous discussions. Despite its simple application, the plethora of brands and types can initially appear overwhelming. Nonetheless, we’ve devised a concise guide to help you determine if filter floss suits your needs, how to use it efficiently, and the benefits you can expect from it.

Article Summary

  • Aquarium filter floss is a mesh material designed to be inserted into a filter to catch large unwanted waste and debris, helping to maintain clear water in your aquarium.
  • Using filter floss in your tank filter is a personal preference, but it can help prevent clogs and reduce the frequency of pump replacements, despite the need to replace the pads weekly.
  • Filter floss can be a beneficial addition to your tank by reducing detritus and waste, but it needs regular maintenance.

Our Top 3 Aquarium Filter Floss

Seapora 4040 Filter Floss Aquarium Filter Pad

Comes with a large roll of filter material, easy to use, and great in both freshwater and saltwater aquariums.

Seapora 4040 Filter Floss Aquarium Filter Pad

The Seapora 4040 Filter Floss Aquarium Filter Pad comes in dimensions of 12in x 6in x 6in and is easy to cut allowing it to be compatible with a large variety of filters. This 12 inch wide roll has 120 inches of material and is an excellent cheap alternative to pre-cut rolls.

AQUANEAT Aquarium Filter Media

This brightly colored pad comes with the added bonus of dual-sidedness allowing for the best of both worlds in terms of sturdiness and flexibility.

AQUANEAT Aquarium Filter Media

Product Description: Dimensions for this product include 72 inches of 12 inches wide and ¾ inch thick and can be cut to fit your individual needs. Be aware that it works well and is worth the money, but users have noticed bits of green and white material floating in their tanks after using it for a longer period of time.

FilterFirst Filter Media Roll

One of the most versatile designs and easiest to use, as an added bonus it was made with no dyes!

FilterFirst Filter Media Roll

A 12 inch wide, 72 inch long, and ¾ inch deep filtering machine these pads have two layers that have different fineness of mesh to ensure all waste is caught.

What is aquarium filter floss?

Filter floss is mesh material that is designed to be inserted into the filter to catch large unwanted waste and debris. It is built with a support layer so water can go through it without bending but is flexible and can fit in most filter units when cut to size.

What does an aquarium filter floss do?

Photo of an Internal Filter
Photo of an Internal Filter

The short answer is that it acts as a net to catch debris. It uses the natural water flow to function and is an extremely efficient aquarium filtration method.

Within a few days of installing you will begin to see the impact reflected in your crystal clear water.

The long answer is that it catches the dirty, large pieces of waste and detritus (organic matter) before they enter your filter’s head, allowing it to clean the water itself instead.

Why should you use a fish tank filter floss

Ultimately whether or not you use it is a personal preference, but it is an affordable strategy for preventing a clog in your tank filter.

Some aquarists like to debate whether the solution is worth the money, as you do have to replace pads at least weekly. However, it does save you money in the future as you don’t have to change your pump as much in the future. The more that you buy the cheaper it is, meaning there is a price break with an upfront investment, but more savings in the long run.

Another concern about this filtration method is that it lowers the flow rate process in your aquarium. While it does slightly reduce the flow of your water it is not enough to cause concern or affect your fish.

Benefits of aquarium filter floss

The main benefit of it is this stuff works, and you can customize it to your own tanks. The pads can be cut to size based on your canister filter, under-gravel filter, internal filter, or other filtration systems. You can also adjust the quality of the sponge based on how many fibers are in the pads. The higher the fibers the more efficient cleaning your system will get.

In other words, think of aquarium floss as a big net catching large particles, detritus, or uneaten food.

How to put filter media in canister filters?

You might be wondering about the process of how you actually install this product.

First, you should measure the area you are adding the floss to, length and width measurements are useful, but depth isn’t much of a concern. I suggest taking a piece of cardboard and a box cutter and sizing it to the dimensions needed. This way you have a template every time you need to change the media.

Once you have your template cut the padding to size and snip any loose ends. Once you have the proper sized piece, place it in your pump and you’re done! 

It should fit snugly but not inhibit the water running at all. There is no correct “up” or “down” so you don’t have to worry about placing it correctly.

Does filter floss remove nitrates?

One of the disadvantages is that it won’t remove the nitrate from your water, in fact, it will likely create more of it. When you think about it this makes sense since the floss will catch the fish food, detritus, and other waste stuff, but it will then be caught and remain in the floss. This will lead to a build up of chemicals like ammonia and nitrites, eventually leading to a large amount of nitrate as a result of the process of the nitrogen cycle.

As nitrogen is highly toxic in large amounts floss needs to be regularly changed to prevent the build up of chemicals in your fish tanks. If you buy a large amount of media originally this should be a fairly simple process of taking one piece of media out and replacing it with the other. 


When replacing media with a new piece be sure to always rinse the pad with cool, dechlorinated water before placing it in your fish tank. This will help ensure that any factory chemicals, as well as any dust, is rinsed off.

What material are aquarium filter floss made of?

Filter pads are made out of a 100% polyester blend. If you’re looking to save when it comes to mechanical filtration you can use polyester quilting material as it generally is lower in price and available at most markets. We’ve also included a link to a quality brand so you can see what it looks like.

To save more and get a high quality look for high load polyester batting. This stuff is more efficient at producing that crystal clear effect in your aquarium. Additionally, the higher quality means in the long run it will be a lower price as you will not have to change it as much.

When looking for your own filter floss it is important to keep a few considerations in mind; 

  1. There shouldn’t be any chance of it falling apart – you don’t want your fish eating media that has come apart and is floating around in the tank. 
  2. Sturdiness – Your floss shouldn’t fall over or have a divot where the water is flowing through it. 
  3. Price – you can get high quality filter floss without having to break the bank. Expensive ones are unnecessary.

If you’re looking for more ways to get more bang for your buck you can keep a bag of all the scraps of media that you cut off from original pieces and use it as a pad. The bag should be made of fine mesh so that it can catch the smaller particles too. Make sure to choose untreated filter floss. Filters that have been treated might contain chemicals that are highly toxic to fish.

Can I use filter floss in an aquarium?

You can use filter floss in your tank in many different ways. Besides placing it in the pump I like using it to wipe and polish the glass of my fish tank. This helps achieve crystal clear water without the need for more costly equipment or chemicals.

How often to replace aquarium filter floss?

Canister Filter
Canister Filter

Since filter floss is doing the majority of the work you should change it fairly often. A good rule of thumb is every 5-7 days. Of course, this depends on the size of your fish tank, and the quality of floss. A thicker piece of floss will not need replacing as often as a thin one as it will take longer to catch debris.


Be aware that a thicker piece of filter floss will also hold more nitrates. If you have a small tank and you use a large piece of floss then it could crash your system. A good rule of thumb is if it can’t fit on the surface of the water in your filter with its lid on then it is too big.

Should I use filter floss?

Using floss is an excellent method of mechanical filtration and is worth using if you’re willing to maintain it.

Do beneficial bacteria live in filter floss? 

There likely is some beneficial bacteria living in your filter floss but not enough that when removed it would crash your system. This is mostly because the floss shouldn’t be in the tank long enough to acquire a colony of bacteria. Additionally, most of it will live on your media which is separate from the floss in your tank.


If you’re starting a new fish tank you can place used media in a mesh bag and let it float in the water. This will allow good bacteria to enter the water of the new fish tank.


The truth of the matter is that quality filter floss can be beneficial to your tank by providing a break in the amount of detritus and other waste in your water.

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