Is Your Filter Sucking Up Baby Shrimp? DIY Matten Guide

If you've ever seen an aquarium with what looks like a giant sponge covering an entire side of the tank, you may have wondered what on earth it is.

That’s a Matten filter!

Matten filters are a simple, highly effective form of sponge filtration that have become particularly popular with shrimp keepers, breeders, planted aquariums and hobbyists looking for a low-maintenance filtration solution.

They may not look as fancy as a canister filter, but don't let their simplicity fool you. A properly sized Matten filter can provide excellent mechanical and biological filtration while creating a huge surface area for beneficial bacteria and microorganisms to grow.

And one of the best things about them?

They’re surprisingly easy to build yourself.

In this guide, we'll look at how Matten filters work, why you might want to use one, how to build one yourself, what sponge density to choose, and which types of aquariums they're best suited to.

What Is a Matten Filter?

A Matten filter, sometimes called a Hamburg Mattenfilter, is essentially a large sheet of aquarium sponge positioned against one side of the aquarium.

Instead of pulling water through a small filter cartridge, the entire surface area of the sponge becomes the filter.

Water is drawn slowly through the sponge and into a chamber or uplift tube, where it is then returned to the aquarium.

This creates two main types of filtration:

Mechanical filtration - The sponge catches particles such as uneaten food, fish waste, plant debris and other suspended material.

Biological filtration - The enormous surface area of the sponge provides a place for beneficial bacteria and microorganisms to colonise.

This makes Matten filters particularly effective biological filters.

How Does a Matten Filter Work?

The secret is the airlift effect.

An air stone is positioned inside a PVC uplift tube. As air bubbles travel upwards through the tube, they carry water with them.

This creates a continuous flow of water up and out of the tube.

As water leaves the uplift tube, more aquarium water is naturally pulled through the large sponge surface to replace it.

This creates a gentle but continuous flow through the sponge.

The result is a filter that can operate using nothing more than:

A large sponge
PVC pipe
An elbow fitting
An air stone
Airline tubing
An air pump

No complicated motor, impeller or filter cartridges required.

Why Use a Matten Filter?

There are several reasons hobbyists choose Matten filters over traditional filtration.

Huge Biological Surface Area

Because the sponge can cover an entire side of the aquarium, you can have a massive amount of surface area available for beneficial bacteria.

This makes them particularly useful for aquariums where biological filtration is important.

Gentle Water Flow

Matten filters can produce a relatively gentle flow compared with some powered filters.

This makes them particularly useful for:

Shrimp
Fry
Small fish
Breeding aquariums
Fish that prefer calmer water

Excellent for Shrimp

Shrimp absolutely love Matten filters.

The large sponge surface quickly becomes covered in biofilm and microorganisms that shrimp can graze on.

You may even notice your shrimp spending huge amounts of time crawling over the sponge picking at all the tiny organisms growing across it.

Pro Tip: Don't think of the sponge as simply a filter. In a shrimp aquarium, it can also become a giant grazing surface!

Difficult for Small Fish to Get Sucked Into

Because the entire intake area is covered by sponge, there isn't one small intake point creating a powerful suction.

This makes Matten filters particularly useful for fry and tiny shrimp.

Choosing the Right Sponge

One of the most important decisions when building a Matten filter is choosing the right sponge.

Sponge density is usually measured in PPI, or pores per inch.

For most aquarium Matten filters, something around 20-40 PPI works well.

A lot of hobbyists settle around 30-35 PPI as a good middle ground.

Coarser Sponge - Around 20-30 PPI

Coarser sponge allows water to move through more easily and is less likely to clog quickly.

It can be useful for aquariums with higher amounts of physical waste.

Finer Sponge - Around 30-40 PPI

Finer sponge provides more mechanical filtration and a greater number of smaller pores for microorganisms to colonise.

However, finer sponge can require more maintenance if the aquarium produces a lot of waste.

Tip: Don't automatically assume that finer sponge is better. You want enough water movement through the sponge without creating excessive resistance.

How to Build Your Own Matten Filter

Building a Matten filter is actually quite simple.

You'll need:

Large aquarium sponge
PVC pipe
PVC elbow fitting
Short piece of PVC pipe
Air stone
Airline tubing
Aquarium air pump
Check valve

You may also want a ruler, marker and drill for preparing the PVC.

Step 1: Measure Your Aquarium

First, measure the side of the aquarium where you want to install the Matten filter.

The sponge should cover most or all of the chosen side wall.

You'll also need to determine how long your PVC uplift tube needs to be.

Ideally, the bottom of the uplift tube should sit approximately 2-3 cm above the aquarium floor.

This gives the water somewhere to enter the uplift tube without having the pipe sitting directly against the substrate.

Tip: Measure twice before cutting your PVC. It's much easier to shorten a pipe than to make one longer!

Step 2: Prepare the PVC Uplift Tube

Take your long piece of PVC pipe and attach an elbow fitting to the top.

Then attach a shorter piece of PVC pipe to the other side of the elbow.

The short section acts as the outlet where the filtered water returns to the aquarium.

You can often use a leftover piece of PVC cut from the main pipe.

Step 3: Prepare the Airline Entry

Drill a small hole into the elbow fitting.

The hole only needs to be large enough for your airline tubing to pass through.

Feed the airline through the hole and down through the PVC until it reaches the bottom.

Attach your air stone to the end of the airline.

Then gently pull the airline back until the air stone sits inside the bottom section of the uplift tube.

When the air pump is turned on, the bubbles will rise through the PVC tube and create the airlift effect.

Step 4: Prepare the Sponge

Take your large sponge and position it against the aquarium wall.

Mark where your PVC uplift tube will sit.

Cut a vertical slit through the sponge where the PVC pipe needs to pass through.

The slit only needs to be large enough for the pipe to fit snugly.

The sponge should sit firmly against the aquarium wall without leaving large gaps around the edges.

Step 5: Install the Filter

Place the sponge against the aquarium wall and position the PVC uplift tube through the opening you've created.

Make sure the bottom of the PVC remains slightly above the substrate.

Once everything is positioned correctly, connect the airline tubing to your air pump.

Don't forget the check valve!

Pro Tip: Install the check valve between the aquarium and the air pump, preferably close to the aquarium. This prevents water from travelling backwards through the airline and into your air pump if the pump stops.

Setting Up the Airflow

Once everything is connected, turn on your air pump.

You should see bubbles travelling upwards through the PVC tube and filtered water flowing out of the outlet.

The water movement should be continuous but doesn't need to be extremely powerful.

Remember, the sponge is doing the filtering.

You don't need to create a huge amount of flow for a Matten filter to work effectively.

Tip: If the flow seems extremely weak, check that the air stone is positioned correctly inside the uplift tube and that there aren't any blockages in the airline.

What Aquariums Are Matten Filters Best For?

Matten filters can be used in a surprisingly wide range of aquariums.

Shrimp Tanks

One of their best applications.

Shrimp can graze directly on the sponge, while the gentle filtration is suitable for even very small shrimp.

Fry & Breeding Tanks

The large sponge surface and gentle flow make Matten filters excellent for raising fry.

There is no small intake grate for tiny fry to become trapped against.

Planted Aquariums

Matten filters can work very well in planted aquariums, particularly low-tech setups where gentle filtration is preferred.

Community Aquariums

They can also be used in community tanks, provided the sponge is appropriately sized for the aquarium and stocking level.

Quarantine & Hospital Tanks

The simplicity of a Matten filter can make it useful for temporary setups where you want reliable biological filtration without complicated equipment.

The Benefits of a Matten Filter

Like every filtration method, Matten filters have their advantages and disadvantages.

Pros

✅️ Huge biological filtration surface area

✅️ Excellent for shrimp and fry

✅️ Gentle water movement

✅️ Very inexpensive to build

✅️ No filter cartridges to replace

✅️ Quiet when paired with a good air pump

✅️ Excellent surface for biofilm and microorganisms

✅️ Can continue providing filtration even during very low-flow conditions

Cons

❌️ Takes up some aquarium space

❌️ Can be difficult to remove once established

❌️ The sponge can become unsightly if covered in debris or algae

❌️ Air pumps are required when using an airlift design

❌️ Fine sponge can clog if the aquarium produces a lot of waste

❌️ Not always the most aesthetically pleasing option for display tanks

Maintenance

One of the biggest advantages of a Matten filter is that it doesn't require constant maintenance.

However, it still needs to be looked after!

As the sponge collects debris, water flow through it can gradually decrease.

When this happens, the sponge can be gently cleaned using old aquarium water removed during a water change.

Avoid rinsing biological filter sponge under untreated tap water, as chlorine or chloramine can damage the beneficial bacteria living within the sponge and may cause a disruption in your cycle, also known as a cycle crash.

If you would like to know more about the nitrogen cycle please feel free to visit our page on Understanding The Nitrogen Cycle.

Tip: You don't need to make the sponge look brand new. A mature Matten filter will naturally develop biofilm and microorganisms, and this is part of what makes it so useful in a shrimp or breeding aquarium.

Matten Filters & Shrimp: Why They Work So Well

If you're keeping shrimp, a Matten filter can be an excellent choice.

Shrimp are natural grazers and spend much of their time searching surfaces for tiny organisms and biofilm.

A mature sponge provides an enormous grazing area.

Instead of having a small filter intake, you've effectively created a giant living filter wall.

Over time, the sponge can become covered in microorganisms that shrimp will happily graze on.

This is particularly useful in breeding colonies, where newly hatched shrimp need access to tiny food sources.

Pro Tip: Don't scrub a mature shrimp Matten filter spotless. Some of that biofilm is exactly what your shrimp are there to eat!

Creating a Natural Moss Wall

One of the really cool things about a Matten filter is that you don't have to leave the sponge looking like a plain black or blue wall.

You can actually attach aquarium moss directly to the sponge and allow it to grow, eventually creating a huge, natural-looking moss wall across the entire side of your aquarium!

This can look absolutely fantastic, especially in shrimp tanks and planted aquariums.

There are several ways you can attach moss to the Matten sponge:

Fishing Line

One of the simplest methods is using thin fishing line to gently secure the moss against the sponge.

As the moss grows, it will gradually attach itself and spread across the surface. Once established, the fishing line can become difficult to see.

Toothpicks

Small pieces of moss can also be secured to the sponge using toothpicks.

Simply place the moss against the sponge and carefully push a toothpick through it to hold it in place.

Tip: Be careful when positioning the toothpicks and make sure they are secure and not sticking out where they could potentially injure fish.

Cutting Slits in the Sponge

Another option is to carefully make small slits in the sponge and tuck pieces of moss directly into them.

This can be a great way to get moss started across the surface without needing lots of fishing line.

As the moss grows, it will gradually spread across the sponge and create a dense natural wall.

Why Grow Moss on a Matten Filter?

A moss-covered Matten filter isn't just about making your aquarium look good.

The moss can provide additional benefits to your aquarium ecosystem.

As the moss grows, it creates even more surface area for microorganisms and biofilm to develop.

This can be particularly beneficial in shrimp aquariums, where shrimp will happily spend their time grazing through the moss and sponge looking for tiny food sources.

The moss can also help trap small particles and organic matter, which can then become another food source for shrimp and other small aquarium inhabitants.

At the same time, the growing plants can absorb nutrients from the water column, contributing to overall water quality.

Pro Tip: A mature moss wall can become an incredibly productive grazing area for shrimp. Don't be surprised if your shrimp spend most of their day crawling through it!

Things to Consider With a Moss Wall

While a moss-covered Matten filter looks amazing, there are a few things you need to keep in mind.

The biggest thing is that you still need to maintain the filter.

The moss doesn't mean you can completely forget about the sponge underneath.

As the filter collects debris, the sponge can eventually become restricted and water flow through the Matten filter may decrease.

Fortunately, Matten filters generally don't need to be cleaned very often. You should only need to clean the sponge when you notice the filter struggling to maintain its normal flow.

However, cleaning a moss-covered filter does require a little more care.

Tip: When cleaning a moss-covered Matten filter, be gentle. Avoid aggressively scrubbing or squeezing the sponge, as you can damage both the moss and the beneficial microorganisms living throughout the filter.

You may also need to trim the moss occasionally.

If the moss becomes extremely thick and dense, it can begin restricting water movement through the sponge.

Regular trimming helps keep the moss healthy while still allowing water to pass through it.

Pro Tip: Don't let the moss completely take over the filter. A healthy moss wall should enhance the filter, not prevent water from passing through it!

With a little maintenance, you can have the best of both worlds, an extremely effective biological filter and a beautiful, living wall of moss.

Common Matten Filter Mistakes

Although they're simple to build, there are a few mistakes worth avoiding.

❌️ Using sponge that is too fine and restricting water flow

❌️ Making the uplift tube too short

❌️ Placing the bottom of the tube directly against the substrate

❌️ Forgetting the check valve

❌️ Cleaning the sponge too aggressively

❌️ Expecting huge water flow from an airlift system

❌️ Leaving large gaps around the sponge where water can bypass the filter

Pro Tip: The whole idea behind a Matten filter is slow, consistent filtration across a large surface area. You don't need to chase high flow rates to make it effective.

Is a Matten Filter Better Than a Sponge Filter?

Not necessarily.

They're both based around the same basic concept, using sponge as biological and mechanical filtration.

The major difference is the amount of sponge surface area.

A traditional sponge filter is compact and sits inside the aquarium, while a Matten filter can cover a large section of the aquarium wall.

For a small shrimp or breeding aquarium, a traditional sponge filter may be more than enough.

For a dedicated shrimp colony or breeding setup, the much larger surface area of a Matten filter can be a major advantage.

If you would like to keep things simple and use a traditional sponge filter, browse our full Sponge Filter Range, they perform just good as a matten filter! They just have a smaller surface area which means less benificial bacteria and food for shrimp to graze on.

Final Thoughts

Matten filters might look incredibly simple, but that's actually part of their appeal.

They provide huge amounts of biological filtration, gentle water movement, excellent grazing surfaces for shrimp and a safe filtration method for fry and small fish.

They're also inexpensive enough that you can build one yourself using a few basic components.

They're particularly useful for shrimp tanks, breeding aquariums, fry grow-out tanks, planted setups and hobbyists who want a simple filtration system with very little ongoing maintenance.

And if you build one yourself, don't forget to give it some time to cycle and mature. That sponge isn't just collecting debris, it's becoming a living part of your aquarium ecosystem.

Sometimes the simplest filtration methods are some of the most effective.

Frequently Asked Questions About Matten Filters

Are Matten Filters good for shrimp tanks?

Yes! Matten Filters are particularly well suited to shrimp aquariums. The large sponge surface provides an excellent area for beneficial bacteria and biofilm to develop, giving shrimp a natural grazing surface. The gentle flow also makes them safe for shrimp and their babies.

What PPI sponge should I use for a Matten Filter?

A sponge around 20-40 PPI works well for most Matten Filter setups, with 30-35 PPI being a popular middle ground. Finer sponges provide more surface area but can clog faster, while coarser sponges allow more water flow and may require less frequent cleaning.

Do Matten Filters need an air pump?

Most Matten Filters are powered using an air pump and air stone. The rising bubbles create an uplift effect inside the PVC pipe, drawing aquarium water through the sponge and back into the tank.

How often should I clean a Matten Filter?

Matten Filters generally don't need frequent cleaning. The large sponge can hold a significant amount of debris while continuing to provide biological filtration.

Clean the sponge when you notice the water flow starting to slow significantly or the sponge becoming heavily clogged. Avoid cleaning it unnecessarily, as this can remove some of the beneficial bacteria and biofilm living on the sponge.

Pro Tip: When cleaning the sponge, gently rinse it in removed aquarium water rather than untreated tap water to help preserve your beneficial bacteria.

Can I put moss on a Matten Filter?

Absolutely! Moss can be attached directly to the sponge to create a living moss wall. You can use fishing line, toothpicks, small cuts in the sponge, or carefully tuck the moss into the sponge and allow it to attach naturally over time.

Will moss growing on the Matten Filter reduce water flow?

It can if the moss becomes extremely dense. As the moss grows, regularly trim it back to prevent it from becoming too thick and restricting water movement through the sponge.

Tip: Keep an eye on the flow from the PVC uplift tube. If it starts becoming noticeably weaker, it may be time to trim the moss or clean the sponge.

Are Matten Filters good for breeding tanks?

Yes! Their gentle filtration and large biological surface area make them an excellent choice for breeding tanks, particularly for shrimp and small fry. They also don't have the same risk of sucking up tiny fry that some traditional filter intakes can have.

Can Matten Filters be used in community aquariums?

They can, although they are particularly popular in shrimp tanks, breeding tanks, fry tanks and smaller planted aquariums. For larger or heavily stocked community aquariums, a Matten Filter may need to be supplemented with additional filtration depending on the aquarium's bioload.

Do Matten Filters remove ammonia and nitrite?

The sponge itself doesn't chemically remove ammonia or nitrite. Instead, it provides a large surface area for beneficial bacteria to colonise. These bacteria are an important part of the nitrogen cycle and help convert toxic ammonia and nitrite into less harmful nitrate.

Can I use a Matten Filter without an air stone?

The traditional setup uses an air stone inside the uplift tube, but the important part is creating the upward flow of water through the PVC pipe. Other methods of driving the uplift can be used, although an air pump and air stone are one of the simplest and most accessible options.

Do Matten Filters need a check valve?

If your air pump is positioned below the aquarium or there is any risk of water flowing backwards through the airline, a check valve is strongly recommended. It helps prevent aquarium water from travelling back towards the air pump if the pump stops.

Can I make a Matten Filter myself?

Yes! One of the biggest advantages of a Matten Filter is that it can be made using relatively simple and inexpensive materials. With a suitable sponge, PVC pipe, elbow fitting, airline, air stone and air pump, you can build a highly effective filtration system yourself.

Are Matten Filters ugly?

That's completely subjective! 😄 While a plain sponge wall might not appeal to everyone, they can actually become a feature of the aquarium. With moss attached to the sponge, you can create a large natural moss wall that becomes part of the aquascape while also providing additional grazing space and biological surface area.

How long does a Matten Filter sponge last?

A good-quality sponge can last for many years when properly maintained. Unlike disposable filter cartridges, you generally don't need to replace the sponge simply because it has become established with beneficial bacteria.

Replace it only when the sponge begins to physically break down or can no longer maintain adequate water flow despite cleaning.

Can shrimp eat the biofilm growing on a Matten Filter?

Yes! This is one of the major benefits for shrimp keepers. As the sponge matures, it can become covered in microorganisms and biofilm that shrimp naturally graze on. A moss-covered Matten Filter can provide an even larger natural grazing area.

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