A sponge filter is the most simple form of filtration. They add surface area for beneficial bacteria, they’re easy to set-up, and they’re very affordable. They’re not perfect for every tank but they can be great options for some tanks. Understanding the best sponge filter for your tank is an important part of fishkeeping. Our favorite sponge filter is the Aquarium Technology Hydro-Sponge Filter.
In this guide, we’ll discuss how to select the best sponge filter and review popular sponge filters options available today.
Best Sponge Filter Options:
What is the best sponge filter?
Aquarium Technology Hydro-Sponge Filter is one of the best sponge filters available on the market. It uses patented foam that is an ideal density for both mechanical and biological filtration, making it highly efficient at both.
It is built for flexibility unlike some of the other sponge filters we reviewed. For example, you can insert an air stone to make it extra quiet. Additionally, If want to increase the flow, you can power it with an aquarium powerhead instead of an air pump. This flexibility gives this option major points.
What is a sponge filter?
At a high level, a sponge filter is extremely simple. It is a piece of foam that filters your entire fish tank. That’s it.
The foam filter can double up as a mechanical and biological filtration unit, giving you two forms of filtration. It is made up of the foam sponge, weighted base, strainer, bull’s eye, and lift tube.
The foam sponge’s quality determines the quality of the overall filter system. The sponge houses the beneficial bacteria that is key to your biological filtration. Better sponges have more surface area and therefore, better biological filtration.
Without a weighted base, your sponge filter would float freely around your tank. This would make it much less effective. The weighted base can be anchored under gravel or rocks. Some sponge filters have a suction cup mount, which are useful bare bottom setups. However, the suction cup can wear out over time, making this a less effective option.
Strainer and Bull’s Eye
The strainer removes food particles and waste from filtering out of your sponge filter. The bull’s eye is the connection point for your airline tubing directly from your air pump.
The lift tube helps transfer water from the sponge filter to the rest of your fish tank. Bubbles run up the lift tube towards the surface of the water. The movement of the bubbles up the tube creates suction that pulls water through the sponge. On more expensive filters, you can use the lift tube to connect the filter to an aquarium power head for more quiet and more powerful filtration.
How does a sponge filter work?
All sponge filters use an uplift tube to pull water through the sponge. To make it happen, first, an aquarium air pump injects air at the bottom of the uplift tube. Air bubbles rise inside the uplift tube. The air-water mixture inside the tube is less dense, which causes the water to rise within the tube, creating suction at the base of the uplift tube. This suction pulls water through the sponge and out of the uplift tube.
Sponge filters and mechanical filtration
Mechanical filtration physically traps particles like uneaten food and waste. It should be used as the first stage of filtration. Mechanical media promotes the growth of beneficial bacteria in your tank.
The water moving through the sponge contains solid particles like uneaten food or dead plant material. The sponge filter traps these particles inside the sponge’s pores.
Because the sponge is physically trapping organic matter, it can become clogged if not cleaned on a regular basis. If this occurs, water flow through the sponge will be reduced.
Sponge filters and biological filtration
Nitrifying bacteria consume ammonia, converting it to nitrite and then to relatively harmless nitrate. The bacteria tend to form colonies in filtration systems..
As water flows through the sponge, it brings fresh ammonia to the nitrifying bacteria where it is consumed and detoxified. This results in healthier water conditions for your aquariums, as harmful ammonia is being directly removed and the helpful bacteria colonies are actively fed with the fresh infusions of water.
What are the benefits of a sponge filter?
There are lots of benefits to using sponge filters.
Easy to use biological and mechanical filtration
Sponge filters are the easiest form of filtration. High quality sponge filters can be used for large aquariums so don’t think you’re limited to other forms of filtration if you have a big tank. Plus, they combine mechanical and biological filtration so its a two for one type of option.
Sponge filters are great for aquariums that require low current dues to the inhabitants. They’re also good to use for tanks with small fish, baby fish, or shrimp. Larger filters can sometimes accidentally suck up small tank inhabitants and maim or kill them, so sponger filters are a safer alternative.
If you haven’t caught on already, sponge filters are cheap! They’re a good option if you have an appropriate tank set-up.
What are the disadvantages of a sponge filter?
Not attractive design
For simple fish tanks or breeder tanks, filter aesthetics don’t matter too much. However, if you’re setting up a beautiful aquascaped tank, the sponge filter is going to cramp your style. They tend to be bulky and difficult to hide.
No chemical filtration
Sponge filters provide both mechanical and biological filtration. However, they lack chemical filtration. Most aquarists want the ability to use chemical media if it is needed. It can be a quick solve for major problems. You can offset the lack of chemical filtration with lots of live plants, but then you’re committed to plant upkeep.
Some fish will try to eat it
Sponge filters are internal filters, meaning that you place them inside the fish tank. This means your fish are constantly around your filter system. It also traps food particles which means it will smell like food to your fish. If you have Plecos or a large, aggressive fish, they may decide to attempt to eat your sponge filter.
Loud and splash water
Sponge filters are not quiet. If you want a quiet aquarium with a sponge filter, you will need to purchase high quality equipment. You will also need to consider the noise level of the air pump.
Also, with sponge filters, you will need to be on the lookout for splashing water. Some sponger filters will splash water from their uplift tubes, which can be annoying from a cleaning perspective (and if you have wood floors!).
How to choose a sponge filter for your aquarium
When you are shopping for sponge filters, it can get overwhelming pretty quickly. There are a few key factors to consider when choosing a sponge filter for your aquarium.
Sponge filters are rated for different tank sizes. For example – “up to 10 gallons” or “up to 60 gallons.” This seems straightforward, but what does this actually mean?
Gallons per hour (GPH) explains how much water can pass through the sponge in an hour. This flow rate is important because water flows through the sponge and the beneficial bacteria remove harmful water issues, and simultaneously feed off of those issues, keeping the beneficial bacteria colonies alive and well.
So, you will need a rating that can support your tank. You will also want to consider the size and shape of the sponge. The larger the surface area, the more beneficial bacteria that the sponge can sustain.
Also, keep in mind that the GPH ratings on filters don’t consider bioload. If your tank is heavily stocked, you will need a filter with more filtration capability versus a less heavily stocked, same size aquarium.
Some sponge filters have biomedia chambers. You can fill the chambers with the biomedia of your choice, or you can remove the chambers and run just the sponges.
You’re not really going to run into price as a huge blocker with sponge filters. They’re cheap and affordable so this is not a significant factor. It is often times worth a few extra dollars to get the top of the line filter.
Lastly, you should read the online reviews of the sponge filter you’re considering to get a sense of how effective the filter is and how durable the equipment will be overall.
Ratings can be a bit subjective, so the reviews will help guide you to the best sponge filter for your tank.
Differences between a Sponge, HOB, and Canister Filter
Sponge filters are useful for collecting physical debris from your aquarium and providing space for beneficial bacteria and biological filtration. Coarse sponges provide a higher flow rate and don’t clog as quickly as finer sponges. However, smaller particles can pass through the coarser holes, meaning that your water won’t be as clean.
HOB filters, or hang-on-back filters, are good for larger tanks that need a more consistent flow rate and better filtering abilities with chemical filtration options. Similar to using a fine sponge, using fine-grained filter pads or sponges will clean your water more by removing microscopic debris, but they’re also prone to clogging faster. HOB filters can be noisy.
Canister filters are the most effective, and expensive, filters available. A canister filter sits outside of the tank and has hoses that can be submerged in the tank to remove and then filter water. Canister filters are often the best choice for easily managing water quality in tanks with plants and numerous plants. They’re quiet and unobtrusive compared to other filter options. They provide superior mechanical and chemical filtration due to pressurization and movement of water through various stages.
Uses for a Sponge Filter
Although sponge filters might not be the best choice for your display tank, due to their cumbersome aesthetic appearance, they are extremely useful for lots of situations.
One of the best uses for a sponge filter is for a breeder tank. Sponger filters are gentle so you don’t face the same risk of killing your small fish and fry by accidentally sucking them into the filter intake.
Because sponge filters can be cycled quickly, they are great for quarantine tanks. A previously cycled sponge can provide immediate beneficial bacteria and biological filtration for a quarantine tank. This is important because when you’re setting up a quarantine tank, you don’t always have a ton of time to cycle the tank like normal so the sponge filter is very useful. Since sponge filters do not use chemical filtration, you are free to use whatever medications without worrying about your media removing or absorbing the medication. The sponge filter also provides gentle flow, which won’t stress out your tank inhabitants.
Freshwater Shrimp tanks
Sponge filters are great for freshwater shrimp tanks. There is no danger that the filter will suck up your shrimp and their babies so safety is great with this approach.. Sponge filters will also grow biofilm on the surface of the sponge, which your shrimp will happily snack on.
Betta fish tanks
Betta fish prefer calm water. They typically have long fins that can be sucked up by powerful filters. Additionally, Betta fish usually live in smaller tanks. All of these reasons make sponge filters an excellent filtration choice.
Small fish tanks
As mentioned before, small fish can get sucked into powerful filter intakes. This will typically gravely injure them or kill them. This makes sponge filters a good choice for small fish. Additionally, small fish tend to live in tanks that are 20 gallons or under, which sponge filters can easily support.
Best Sponge Filter options:
- Aquarium Technology Hydro-Sponge Filter
- Hikari Bacto Surge Foam Filter
- Aquaneat Sponge Filter
- Uppettools Aquarium Biofilter Sponge Filter
- Huijukon Sponge Filter
- hygger Aquarium Double Sponge Filter
This is one of the best sponge filters available on the market. Aquarium Technology uses patented foam that is an ideal density for both mechanical and biological filtration. This sponge filter uses a free-standing heavy base that locks securely in place.
The construction allows for flexibility on how you implement your filtration. For example, you can modify the filter by inserting an air stone to make it extra quiet. Additionally, If want to increase the flow, you can power it with an aquarium powerhead instead of an air pump.
- Provide both mechanical and biological filtration
- Can be operated with an air pump and stone, or a suitable powerhead
- Hydro V is rated for aquariums up to 125 gallons
- Patented, quality foam
- Can be modified to be make more silent
- Larger models can operate via powerhead
- More expensive than other sponge filters
- No chemical filtration
The Hikari Bacto Surge sponge filter uses a classic weighted base design. This filter uses a highly porous sponge filter that maximizes biological filtration for beneficial bacteria and is better quality than most filters on this list.
The filter is placed on the bottom of the aquarium. From there, it is connected to your air pump. The sponge will capture suspended debris floating in the water. It also contains enough surface area to build beneficial bacteria colonies.
Hikari Bacto Surge sponge filters are available in Large and Small versions. The large version is really large and rated to handle up to a 125-gallon tank. We’d recommend not pushing that limit, but would feel confident with something like a 55-gallon tank for the large.
- Small size reported to work well for 10 and 20 gallon tanks
- Excellent foam quality
- Can be modified to be make more silent
- Some issues with floating sponge because not enough weight in base
- No chemical filtration
The Aquaneat Sponge Filter is a classic sponge filter design and rated for up to 60 gallons. It is a large sponge filter, so it will work best in 20 gallons or above. Putting it in a smaller tank will take up a lot of space.
This filter has an air infusion chamber that produces tiny bubbles which increase the oxygen solubility. This kit includes 1 sponge filter, 4 feet of airline tubing, 4 suction cups, 1 control valve, 1 tee, and 1 non-return check valve.
- Kit comes with everything needed except air pump
- Safe for small fish
- Safe for saltwater tanks
- Easy to set-up and clean
- Good value
- No instructions included. Need to look them up online.
- Strong bubbles
The Uppettools Aquarium Biofilter Sponge Filter can be thought of as a combination between a sponge filter and a corner filter. The Upettools filter is one of the quieter options on this list.
Water flows through a ridged sponge and then passes through a chamber filled with ceramic biomedia (media is included). Over time, you can also change the type of media.
This filter is on the smaller side and only rated for tanks up to 15 gallons
- Rated for tanks up to 15 gallons
- Quiet for a sponge filter
- Good filtering capability
- Reports of air tubing leaking
- Large filter size despite small tank rating
The Huijukon filter is similar to the Upettools filter, but it is rated for a much larger capacity. It’s rated for up to 60 gallons.
It is a dual sponge model and has biomedia chambers. The media is not included so you will need to plan to purchase media if you want to use the chambers. Otherwise, you can remove the chambers and run the sponges only.
Because of its construction, it cannot be modified with an airstone to reduce noise. It also lacks chemical filtration.
- Dual sponge filter
- Rated for tanks up to 60 gallons
- Contains chambers for biomedia
- Double 9-layer ribbed sponges design with high density porous sponges for max beneficial bacteria surface area
- Can’t be modified
- No Chemical filtration
The Hygger double sponge filter is a good choice. It has two media chambers that come with good-quality ceramic media. You can also replace the pre-filled ceramic media with carbon and have a 3 stage filter. It is best suited for tanks in the 10 to 40-gallon range. It uses two strong suction cups to stay in place.
The Hygger double sponge filter can not be modified with an airstone.
- Double sponge model
- Comes with a bag of ceramic media balls.
- Can be used in freshwater and saltwater tanks
- Easy to install
- Sponges good quality
- Users report very effective at cleaning
- Requires air pump
- Requires sponge changes about every 6 months
How to make your sponge filter quiet
Sponge filters can be noisy so a common question is how to modify your filter to make it operate more quietly. Some models can be taken apart so that you can insert an air stone in the bull eye. This video shows methods to make your sponge filter quiet.
How to clean a sponge filter
Luckily, like most things to do with sponge filters, cleaning a sponge filter is easy. First, siphon some water out of your tank into a large bucket. Remove the sponge filter. Squeeze the sponge in the old tank water several times to get out the debris. Be prepared – there can be a lot of stinky debris! Squeeze it a few times until most of the water coming out is mostly clear. Discard the water and put your sponge filter back together. That’s it!
You will want to clean your sponge filter at least once per month, maybe more frequently depending on the size of the pores in the sponge. Fine pores tend to clog more easily.
It is a great idea to clean your sponge when doing a water change because you will naturally have tank water in buckets. We recommend putting a cover on the sponge, like a fish bag or zip lock, when pulling it out. This will help prevent the debris from escaping back into your tank.
And do not use regular tap water for cleaning, as the chlorine in the tap water will kill the beneficial bacteria living in the sponge. If you do this, you will have to start all over with cycling the sponge, which can have negative effects for your tank inhabitants.
Sponge Filter FAQs
Are sponge filters good for fish tanks?
Yes, sponge filters are good for a lot of fish tanks. Sponge filters are helpful due to their gentle flow which is great for breeding tanks, quarantine tanks. betta tanks, and shrimp tanks. All of these tank situations do best with gentle flow situations. Small tanks are also good candidates for sponge filters.
Do sponge filters clean the water?
Yes, sponge filters clean the water through mechanical and biological filtration. Mechanical filtration physically removes debris from the water, such as uneaten fish food and fish waste. Because of the surface area of the sponge, beneficial bacteria colonize and convert ammonia to less harmful forms, thereby improving your water parameters.
Is a sponge filter enough?
The answer depends. If you’re running a small tank, breeding tank, quarantine tank. betta tank, or shrimp tank, a sponge filter is an excellent choice. A sponge filter can be enough for most freshwater aquariums assuming it is rated appropriately for the tank. Depending on the tank, you might need to add a second filter if your tank is quite large or you might need to include a power head for water flow.
How long do sponge filters last?
Sponge filters can last a long time, up to several years. Their longevity will partially depend on the initial foam quality and how often and how vigorously you squeeze them out. A lot of manufacturers recommend replacing them every 6 months, but we think this is a ploy to sell more sponges. Many aquarists report using the same sponge for years without ill effect.
Does sponge filter clean fish poop?
Yes, sponge filters trap fish poop via mechanical filtration, or physically catching the fish waste in the pores of the sponge. They can also catch other forms of debris such as dead plant material and uneaten food.
Sponge filters are a critical piece of equipment in both fresh and saltwater tanks. They are integral to clean water parameters, using both mechanical and biological filtration to keep water sparkling. They help your tank’s nitrogen cycle by removing organic waste products before they decompose into ammonia and housing colonies of beneficial bacteria.
Our all-around recommendation for the best sponge filter is the Aquarium Technology Hydro-Sponge Filter. If you’re looking for the best sponge filter on the market, this is it.
Do you use a sponge filter in your tank? What is your favorite sponge filter?