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Aquarium Basics: The Sponge Filter for Fish Tanks

Using an aquarium sponge filter can benefit your tropical fish a lot. This sponge filter may be unsuitable for every fish tank, but for most fish tank hobbyist and even breeders, the basic sponge filter is an amazing and simple filter that does a great job of keeping your tanks clean.

Most fish aquarium keepers have no notion on how to use the sponge filter or are unaware that it exists at all. Opting first to go with a plugin mechanical or canister filter, the sponge filter is often overlooked. Don't be so quick to disregard the sponge fitler, it can do an amazing job.

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What exactly is a sponge filter?

A sponge filter is a porous sponge made up of an air tube which acts as a filtration mechanism in an aquarium. A sponge filter provides biological and mechanical filtration of accumulated particles and bio-wastes in the aquarium water. This sponge filter comes in various shapes and sizes and pore sizes as well to suit each filtration needs for your aquarium. It can also run on air pumps and powerheads.

However, a sponge filter does not contain any chemical filtration. But, you can secure a carbon bag to the sponge if you need chemical filtration.

What are the benefits of a Sponge Filter?

Some of the benefits of the Sponge Filter are:
• It is simple and easy to use. It can power on basic methods like air pumps and powerheads.
• It performs biological filtration efficiency.
• It is the best filter for a Betta fish.
• It is cost-efficient and affordable.
• It is an ideal filter for breeding fish and suitable for raising fry or hospital tanks.
• It is easy to clean. All you need to do is to take out the sponge and squeeze it.
• It is a suitable choice for larger fish like Discus or Angel aquariums.
• It can work on HOB filters as a pre-filter option.
• It is also excellent for aquatic plants as it retains higher CO2 levels in the aquarium.

How does a Sponge Filter work?

A sponge filter operates by using the porous sponge as a biological and mechanical filter that sucks in water and filters any waste particles in the aquarium water. The porous material offers an excellent home for good bacteria to breed and grow. The beneficial bacteria turn harmful nitrates into less toxic nitrates which can be removed by frequent water changes.

An air stone performs the suction which will pull the water through the sponge. A powerhead can also be used to create a suction effect. This suction effect is known as "uplift" and will draw the water through the sponge, which will filter it and release the water back into your aquarium.


You can use a powerhead when higher water flow level is required or when cross-current is necessary for your big tanks.

Air pump

An air pump is best for fry, breeding and hospital tanks. You can use it when you need low current filters. The air pump is simple and easy to use and is ideal for first-timers.

Why is the Sponge Filter a suitable choice for your tropical fish tank?

The sponge filter provides a low water current level with the help of an air stone. The filter benefits betta fishes, and small shrimps. It creates a safe habitat for the fish as your betta fish cannot thrive in strong water current.

The sponge filter is an ideal choice for your planted aquariums. It helps to retain the CO2 in the water which will help your aquatic plants to thrive in your aquarium.

The sponge filter provides exceptional biological filtration.

The sponge filter can also connect with HOB filters as a pre-filter which can aid in preventing the debris from jamming the HOB canister. It also enables the filter cartridge in the HOB to last longer.

What are the downsides of the Sponge Filter?

The most significant drawback about the sponge filter is its lack of chemical filtration which can be done through the use of tools like activated carbon when you are medicating your fish. The other negative thing regarding the sponge filter is that it cannot be too appealing. It can be too big, broad and unattractive, so it is best you hide the sponge filter behind some rocks or other decor. You can also keep the sponge filter concealed behind aquatic plants in your planted aquarium.

How to use a sponge filter?

Using a sponge filter is simple. It comes as a pre-assembled media, so there is nothing you need to do except to connect it to an airline, and an air pump or a powerhead. The Tetra Whisper Air Pump is a recommended choice if you are going for the air pump.

How to clean a sponge filter?

A Sponge filter is easy to clean. Regular maintenance of the sponge filter is required to prevent wastes and particles from clogging it. Cleaning the sponge filter every few weeks or so is advisable for the well-being of your aquarium.

You would know it is time to clean the sponge filter when you notice the water around the sponge starts to lag. To clean the sponge filter, you will need to do a water change. Retain some of the used aquarium water in a bucket. Gently remove and pull the sponge filter out without dropping any debris or the dirty water into the aquarium. Next, immerse the sponge filter into the used water and rinse it thoroughly and repeatedly until it is free of debris. Once done, put it back again to its place in your tank. Throw the used and dirty aquarium water in the bucket and fill up the tank with conditioned water.

Your aquarium will be free of dirt and debris and therefore will not clog if you clean the sponge filter frequently. Additionally, the sponge filter will last longer.

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