Aquarium filters are essential to providing your fish with clean and healthy water. When it comes to choosing a filter for your aquarium, you have lots of options, and many fish owners can become overwhelmed. Depending on the size of your tank, your inhabitants and your own personal preferences, we’ll guide you to the best options available. No matter what type of filtration you select, remember that proper maintenance will keep it working long and hard.
“Filters are a vital component of any aquarium. Good fish health requires filters to be set up correctly and maintained regularly. All aquatic animals will require a filter of some kind,” Dr. Jessica Fox, Certified Aquatic Veterinarian, told The Spruce Pets.
Our best overall selection, the AquaClear Power Filter, comes in a wide range of sizes, contains filter media that is almost indestructible and has been successfully cleaning this author’s tank for almost 10 years. In my career as a private fish practitioner, I have seen every type of filter and have frequent discussions with my clients about various available models. When it comes to filters, you really can’t beat AquaClear overall.
AquaClear Power Filter
Comes in many sizes
Good for most fish system
Motor can require some finessing
The AquaClear filter is a hang-on the back with a cleverly disguised foot brace to accommodate all sizes of aquariums. It contains a basket that can contain any type of filter media you choose, and comes preloaded with a durable sponge filter, a small bag of activated carbon and zeolite media. The sponge filter works well on its own—the sponge in our home model has lasted almost 10 years at this point. (Never replace your filter media—unless it's literally falling apart.)
The AquaClear comes in a wide variety of sizes and is relatively quiet at a reasonable price point.
Price at time of publish: $39 (10-30 gallon)
Size: 5-20 gallon, 10-30 gallon, 20-50 gallon, 40-70 gallon, 60-110 gallon | Filter Media: Sponge, carbon, zeolite
MarineLand Penguin Power Filter
Easy to set up
Small particulate filtration
Filter clogs easily
Mesh filter does not hold up over time
Most models of the Marineland Penguin Bio-Wheel run under $30 and its useful for a wide range of mid-size aquariums. These filters feature a rotating paper filter, which is a pain to keep clean, so clogs are common. This filter also contains a mesh filter media packet, which can be replaced with a more solid sponge for better performance—an easy upgrade.
Price at time of publish: $21 (20-30 gallons)
Size: 10 gallon, 10-20 gallon, 20-30 gallon, 30-50 gallon, 50-75 gallon | Filter Media: Paper, mesh, sponge
Best for Small Tanks
Fluval U2 Underwater Filter
High quality sponge
Easy to maintain
When we tested internal filters, we found the Fluval U2 Underwater filter to be the best compact option for small aquariums. This type of filter rests within the actual aquarium, so it will take up a bit of space, but can be customized and has a large filtering capacity.
Price at time of publish: $28
Size: 15 gallon, 12-30 gallon, 24-40 gallon, 34-65 gallon | Filter Media: Sponge
Best for Betta Tanks
Tetra Whisper Internal Power Filter
Hangs below water line (cannot fill tank entirely)
Cannot adjust flow
When it comes to keeping your betta happy, outflow from your filter is a serious issue. Bettas absolutely need a filter, but fast flowing currents from a filter return can push them around, causing traumatic injuries and serious nutritional deficits from having to swim constantly. Therefore, if you have a betta, you are best off with a low-flow filter, such as the Tetra Internal Power Filter. Although not the greatest filter media, this can easily be swapped out with another sponge filter cut to the correct size.
Price at time of publish: $10 (10 gallon)
Size: 4 gallons, 10 gallons, 30 gallons, 40 gallons | Filter Media: Mesh
Best for Large Tanks
Fluval High Performance Aquarium Canister Filter
Large volume capacity
Can customize filtration
Cumbersome to clean
Takes up considerable space
When it comes to providing filtration for a large system, you may want to consider multiple filtration options used in combination. However, if you are limited on power supply and space, you should check out the Fluval High Performance Aquarium Canister Filter, that can handle up to 250 gallons (FX4) or 400 gallons (FX6). Like its smaller counterpart also listed, this canister filter was smartly designed and comes with twin output nozzles for multi-directional flow return.
Price at time of publish: $310 (FX4)
Size: 250 gallons, 400 gallons | Output: 700 gph (FX4), 925 gph (FX6) | Filter Media: Carbon, zeolite, biofoam, quick-clear, sponges
Penn-Plax Premium Undergravel Filter
No moving parts (good for small/sensitive fishes)
Can decrease tank maintenance
Very difficult to clean
Can be tricky to get set up correctly
Requires an air pump, sold separately
Sure, under-gravel filters may sound like a good idea, but unless you stay on top of your maintenance and have a low bioload in your tank, they have a tendency to clog. It is critical that you read the set up instructions carefully and keep up with your maintenance. The Penn-Plax Undergravel filter contains plates, adjustable lift tubes, airline tubes and activated carbon filters. This product works by an airlift system, and there is no air pump included, which will be required in order for this product to work correctly.
Price at time of publish: $20
Size: 10 gallon, 20 gallon, 29 gallon, 55 gallon | Output: None (separate air pump required) | Filter Media: Carbon
Hipanda Filter Foam Sponges
Fits in any filter
May need to cut to size
Not preferred for large filters
Not all filters come with the best filter media, so thankfully, you can swap it out for a Hipanda dense filter foam sponge. Your filter media should last for years and not fall apart like many mesh pads. This foam sponge can be cut to the exact shape of your filter, no matter which one you decide. To clean, simply squeeze it out in some waste tank water and replace!
Price at time of publish: $9
Size: 7.5 x 4.7 x 2.75 inches, 9 x 9 x 1 inches, 10 x 4.7 x 2.75 inches | Filter Media Type: Sponge
Fluval Performance Canister Filter
Customizable filter media options included
Easy to clean (compared to other canisters)
Priming valve attached
Seal around canister can have issues aligning if loaded incorrectly
Requires complete disassembly for cleaning
The Fluval Performance Canister filter has been well thought out and has many handy features for canister filters. It can contain a variety of filter media to suit your needs, but read the instructions carefully. When it comes to canister filters, cleaning and disassembly can be a bit of a pain, but the quick release hoses and filter components with easy access handles make this filter less cumbersome.
Price at time of publish: $145
Size: Up to 30 gallons, 45 gallons, 70 gallons, 100 gallons | Output: 27 gph pump cycles 4 gallon aquarium 6x hour | Filter Media: Carbon, zeolite, biofoam, quick-clear, sponges
Best Fluidized Bed
QANVEE Fluidized Moving Bed Filter
No moving parts
Limited filtration capacity
No mechanical filtration
Requires additional air pump
Fluidized bed filters can contain either sand or plastic biomedia that is kept constantly churning by water flow. The QANVEE Fluidized Moving Bed Filter comes with K1-similar media that runs off an air pump. This filter has no moving parts and will also provide aeration to your tank. This type of filter can be used in conjunction with other types of filter or as the only filter in aquariums with a very small amount of fish and/or invertebrates.
Price at time of publish: $15-18
Size: 2.6 x 7.4 inches (LH300), 3 x 9 inches (LH600) | Output: Varies depending on air pump attached | Filter Media: Plastic
Aquapapa Bio Sponge Filter
No moving parts
Ideal for breeding tanks, shrimp, and bettas
Requires air pump, sold separately
Sponge filters, such as the Aquapapa Bio Sponge filter, are ideal for shrimp tanks, breeding tanks and betta tanks. These filters do not provide a ton of water flow, so you need to use them only in very low bioload tanks. Sponge filters rely on airlift systems, or the pull of air bubbles rising to the surface, to create a mild current. These sponges can get easily clogged, so be sure to rinse them routinely in waste tank water.
Price at time of publish: $18 (3-pack)
Size: 4.5 x 8 inches | Output: depends on type of air pump purchased (not included) | Filter Media Type: Sponge
When it comes to selecting a filter, you just can’t beat the AquaClear Power Filter. I’ve been using one for almost 10 years, and it is the best pick for most aquarium tanks. If you’d prefer a canister model, the Fluval Performance Canister Filter has a size that will make your fish happy and you can customize the filtration components to your heart’s content.
What To Look For
Filter Media Type
There are many different types of filter media available for home aquariums. Here are some of the types you may encounter:
- Mesh: This type of filter is very flimsy and cheap. It may contain a few flecks of activated carbon, but mostly is designed to fail. We recommend swapping this out for a sturdy sponge, cut to size, before you start running your filter.
- Activated carbon: You are not required to use carbon in your filter. Carbon can be used to remove various compounds from your water, but your water may already be healthy enough. Carbon will deactivate water-based medications and some other water treatments.
- Sponge: This type of filter media should last you for several years. To clean it, wring it out in a bucket of waste tank water, such as after siphoning. Never replace it, unless it is about to fall apart, or rinse it in chlorinated tap water or heated water.
- Zeolite: These small ceramic rocks are designed to provide housing for good bacteria and bind with some nitrogen compounds. It will lose its absorptive powers overtime, but can be recharged in a saltwater solution.
- Plastic: These small beads are strategically designed with a high surface area for growing good bacteria with optimal water flow. These should be allowed to move around freely for best use.
The bigger your aquarium, the more water you will need to filter. Most filters are designed to turn over the entire volume of the tank within 30-60 minutes. Any longer than that could have serious consequences to your fish and invertebrates. Depending on your species and setup, you may need to go a little lower or higher-powered filtration in order to provide the ideal environment. Bettas, for example, will require a lower flow, whereas some corals will require a higher flow due to their placement and anatomy.
Your filter should not be overtly noisy. However, the larger your filter, the more powerful the motor needs to be, so you may note some noise. Never attempt to muffle the noise by covering or insulating your filter. This will cause it to overheat and malfunction. If you notice significant noise or an increase in noise from your filter, contact the manufacturer for troubleshooting.
There is no one perfect way to install a filter. Ideally, you should set up your filter to circulate all of the water within your aquarium. For hang-on models, you should ideally set up the intake towards the middle of your tank or opposite from a powerhead or aerator. This will create a current in your tank to ensure all of your water is filtered.
Canister filters require a bit more work to install. Usually, these are higher-power pumps that can create high currents in your tank. Try to baffle the outflow or direct it along the longest axis of your tank. This will prevent your fish from having to swim too much and wearing themselves out. With whatever filter you use, read the installation instructions carefully and if you are unsure of anything, contact the manufacturer or visit their website.
How do aquarium filtration systems work?
Aquarium filters work by providing mechanical, biological and chemical filtration. Mechanical filtration removes particulates from your tank water, produced by inhabitant waste. Biological filtration housing is provided in your filter media (types listed above). This allows beneficial bacteria to convert ammonia, the primary fish waste product, into nitrite and then nitrate. Nitrate is used by algae and plants as a good source and is not as toxic to fish. Chemical filtration, such as those provided by activated carbon, change the chemical composition of various compounds in your solution, such as chlorine and chloramines. As water passes through your filter, all of these filtration methods go to work on your fishes’ environment, making it healthier for them.
What are the types of aquarium filters?
There are many different types of aquarium filters:
- Hang-on filters: these filters hang on the side of your aquarium or tank
- Canister filters: these are external and self-contained and use hoses to run water back and forth from your aquarium
- Internal or box filters: these filters remain in the aquarium and must be fully or partially submerged
- Undergravel filters: these are plastic mats that reside under your substrate and capture debris. They need to be flushed regularly so the debris does not get trapped
- Sponge filters: these are very simple filters that use an airlift from an air pump to slowly circulate water through a dense sponge
How do you clean an aquarium filter?
The best way to clean an aquarium filter may vary slightly depending on the type of filter you choose. It is recommended that you disassemble the various components per the manufacturer's instructions. Rinse all of your filter media and components gently in a bucket of waste tank water, such as one collected from gravel siphoning. Never rinse your media in chlorinated tap water or hot water. This will kill all of the beneficial bacteria you have worked so hard to cultivate! Before you plug your system back in, ensure that it is primed so the pump will work correctly and not get burned out.
How often should I change my aquarium filter?
Never. You should never replace your aquarium filter unless it is broken or your filter media is literally falling apart. Just like in our cleaning recommendations, if you throw away your filter, you are essentially starting from scratch! I know it says to replace your filter every # months, but please ignore it! Trust me; I’m a certified aquatic veterinarian with 10 years experience working with pet fish. Use the money to buy your fish a new decoration or some fresh food.
Why Trust The Spruce Pets?
In her 10 years in private fish practice, Dr. Jessie Sanders DVM, CertAqV has seen thousands of home aquarium setups. Filtration and filters are discussed almost every day and she has tried most of the models above for herself and her company. When it comes to filters, your fishes’ lives depend on them, so keep it clean and well maintained. And those AquaClear filters are awesome. She's had the same one on her tank since 2014, with the same sponge!