Every budding aquarist cares about the quality of the water in their aquarium. It is (arguably) THE most important aspect of the hobby. In order to get the highest quality of water, you should look towards the best aquarium filter for your fish tank.

This article will first discuss what to look for in a great aquarium filter and then we will review seven filters to fit your needs.

Winner
Penn Plax Premium Under Gravel Filter System - for 40-55 Gallon Fish Tanks & Aquariums
Cascade CCF2UL Canister Filter For Large Aquariums and Fish Tanks – Up To 65 Gallons, Filters 185 GPH
Fluval Canister Filter, FX6 Filter (400 Gal)
AZOO Mignon Filter 60
Aqua Clear - Fish Tank Filter - 40 to 70 Gallons - 110v
Aquarium Filter Hydro-Sponge IV by Lustar, for Aquariums up to 80 Gallons
Penn Plax Premium Under Gravel Filter System - for 40-55 Gallon Fish Tanks & Aquariums
Cascade CCF2UL Canister Filter For Large Aquariums and Fish Tanks – Up To 65 Gallons, Filters 185 GPH
Fluval Canister Filter, FX6 Filter (400 Gal)
AZOO Mignon Filter 60
Aqua Clear - Fish Tank Filter - 40 to 70 Gallons - 110v
Aquarium Filter Hydro-Sponge IV by Lustar, for Aquariums up to 80 Gallons
$17.02
$61.00
$339.99
$14.76
$49.97
$15.76
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Winner
Penn Plax Premium Under Gravel Filter System - for 40-55 Gallon Fish Tanks & Aquariums
Penn Plax Premium Under Gravel Filter System - for 40-55 Gallon Fish Tanks & Aquariums
$17.02
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Cascade CCF2UL Canister Filter For Large Aquariums and Fish Tanks – Up To 65 Gallons, Filters 185 GPH
Cascade CCF2UL Canister Filter For Large Aquariums and Fish Tanks – Up To 65 Gallons, Filters 185 GPH
$61.00
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Fluval Canister Filter, FX6 Filter (400 Gal)
Fluval Canister Filter, FX6 Filter (400 Gal)
$339.99
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AZOO Mignon Filter 60
AZOO Mignon Filter 60
$14.76
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Aqua Clear - Fish Tank Filter - 40 to 70 Gallons - 110v
Aqua Clear - Fish Tank Filter - 40 to 70 Gallons - 110v
$49.97
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Aquarium Filter Hydro-Sponge IV by Lustar, for Aquariums up to 80 Gallons
Aquarium Filter Hydro-Sponge IV by Lustar, for Aquariums up to 80 Gallons
$15.76
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Last update on 2020-02-17 / Affiliate links / Images from Amazon Product Advertising API

Benefits Of An Aquarium Filter

Aeration Of The Water

Just like all other animals, fish breathe oxygen. However, instead of taking it from the air like humans they use their gills to take oxygen from the water.

With this fact in mind, you will realize oxygen-rich water is needed for your fish to thrive. Filters help to aerate the water.

Some aquarium filters infuse oxygen into the water as they transfer it over filter media. Other systems agitate the water which provides more surface area for oxygen transfer. Don’t overlook a filter’s ability to aerate when picking out a product.

Creating Water Movement

All filter systems will create water movement as they operate. Moving the water column will require your fish to swim more actively.

Any debris caught in the moving current will move towards the filter and be removed from your tank. Water movement also helps to avoid any stagnant ‘still water’ or ‘dead areas’ in the tank where toxic gas can build up.

Different styles of filters create a current in various ways, and the strength of the movement generated may be important when housing some types of fish.

Providing A Home For Beneficial Bacteria

An established aquarium contains more than your pets. It is also home to bacteria, some of which are necessary for maintaining water quality. While these bacteria live throughout the aquarium, a filter system provides the highly oxygenated water that allows colonies to thrive. Different types of beneficial bacteria will grow in your filter media and form part of the nitrogen cycle.

Food debris, fish waste, and gases created as the fish breathe produce ammonia in the water. Ammonia is highly toxic for your fish and needs to be removed from the water column. A bacteria named Nitrosomonas uses oxygen to convert the ammonia into the less toxic nitrite. While not as toxic, nitrite is still dangerous to aquarium inhabitants.

As the nitrite levels rise, a bacteria known as Nitrobacter will convert it into nitrate. This is relatively harmless to your fish, except in high concentrations. Nitrates can be used by live plants or removed through a partial water change. The nitrogen cycle is explained further in this short video…

It is important to remember that the bacteria colonies that have established themselves in your filter should not be disturbed. When cleaning and performing maintenance, it is important that you do not destroy the colonies, or the aquarium’s nitrogen cycle will be broken.

We also recommend that you “cycle” a new tank before adding fish to it. This article from the staff at Doctors Foster And Smith touch on cycling a new aquarium’s filters and pumps.

A Filter Does The Work For You!

Without an aquarium filter, you would be required to replace a larger volume of the column during a water change. You would also have to change the water more often.

Proper filtration helps to prevent algae build-up in the tank, and it also aids with water clarity. Aquarium filters let you spend more time watching and less time working.

What Are The Methods Of Aquarium Filtration?

Mechanical Media: This product is made from chemically neutral materials. It is used to remove pieces of debris from the water. The pours of this media vary in size. When using multiple media in a filter system, mechanical media is placed in the first position.

Biological Media: The materials that make up this media are inert and provide the home that good bacteria will thrive in. It takes dissolved materials and breaks them down further. It should not be cleaned or replaced unless it becomes too clogged to function properly. In a multi-media system, it is often located behind mechanical media.

Chemical Media: This material is used to leech particular materials from the water column. It is often made of carbon or resin. It is not as common as the other types of filter media. The staff at Animal Planet have written about these materials in more detail.

Types Of Aquarium Filters

Cannister Filters

These systems use tubing to move the water between the aquarium and the filter. Due to their size, these systems can use all three media types. The canister is pressurized which allows it to force water through a finer straining process. These systems work great on tanks that are 40-gallons or larger.

Fluidized Bed Filters

These devices hang off of the tank where water is forced through chips or granules that are suspended. These filters provide great biological and moderate mechanical filtration. Chemical media does not work well in these setups.

Hang on Back / HOB Filters:

Also known as a power filter, this device is very popular amongst hobbyists. The water is pulled into the filter through siphoning. These units use all three media types in their process.

Internal Filters

This system is placed in the aquarium, often near the substrate. Some internal systems need an air pump to move water through them. They make use of all media types. An internal filter’s small smaller size makes them a great choice for smaller tanks.

Sponge Filters

These simple setups use air to force water through the sponge material. They provide adequate biological and mechanical filtration. They are best used in breeding and quarantine tanks, or aquariums that house small fish.

Undergravel Filters

These systems are placed under the substrate and use the gravel as a mechanical media. Water is moved in uplift tubes by air pumps or a power head. This setup is not good for biological or chemical filtration.

Wet/Dry Filters

The trickle filter is a great biological filter as it provides a lot of air contact. They are often used on saltwater tanks due to this feature. Chemical media can be placed in the system, but mechanical media is limited to larger pours for the water to travel through.

Best Aquarium Filter Reviews

Penn Plax Undergravel Filter – Designed to Fit 40/50 Gallon Tanks

Penn Plax Premium Under Gravel Filter System - for 40-55 Gallon Fish Tanks & Aquariums
  • Undergravel filter system includes 4 filter plates (each measuring 11.5" X 11.5") with extra large 1 inch adjustable lift tubes.
  • Filter is suitable for most 40 and 50 gallon aquariums. Clips to hold each section securely together are included.
  • 2 carbon filter cartridges remove odors, and water discoloration by trapping the pollutants in the pores of the carbon.
  • This undergravel filter hides from view for maximum aesthetics. Safe for use in both freshwater and saltwater tanks.
  • Effortless setup and easy maintenance make this premium undergravel filter a must have for all home aquariums.  Simply place filter plates at the bottom of the tank and cover with gravel.

Last update on 2020-02-17 / Affiliate links / Images from Amazon Product Advertising API

This product from Penn Plax makes use of four plates that are placed along the bottom of the tank. Two one-inch uplift tubes provide plenty of water movement. They are adjustable, providing some versatility.

 This under gravel filter system is easy to set-up.   

The manufacturer provides two Filt-A-Carb cartridges that can provide chemical filtration as the water re-enters the tank. The high pour airstone heads are capable of providing plenty of water movement within the uplift tubes. The filter system can be put together in as little as five minutes.

 The plastic used for construction feels brittle.   

This filter may be a great choice for users who are looking for a filter that requires little maintenance. The product is also available in other tank sizes.

Pros
  • The filter system is easy and quick to put together
  • This filter is completely hidden underneath the gravel
  • It provides good mechanical filtration by using the existing substrate
Cons
  • A separate air pump or powerhead will be required to use this unit
  • It does not provide good support for biological filtration
  • It provides good mechanical filtration by using the existing substrate

Fluval Canister Filter, FX6 Filter (400 Gal)

Sale
Fluval Canister Filter, FX6 Filter (400 Gal)
  • Multi-Stage Filter that produces healthy aquarium water, freshwater or marine aquariums
  • Features Smart Pump Technology for optimal filter performance, efficiency and management
  • Self-starting filter-just add water and plug in. Head height (maximum): 3.3 m (10.8 feet)
  • For aquariums up to 400 gallons

Last update on 2020-02-17 / Affiliate links / Images from Amazon Product Advertising API

The FX6 Canister Filter may be a great choice for those who have a large aquarium reaching up to 400-gallons. This Fluval product can cycle 563-gallons of tank water per hour.

 A monthly maintenance reminder is a great feature for those of us who are forgetful.   

The system includes electronic monitoring of both impeller speed and the pump’s power, a nice addition that helps the system run efficiently. An AquaStop valve allows a user to turn off water flow with a simple twist on the lever.

 This high-volume filter doesn’t come cheap.   

The beveled screen on the intake strainer prevents debris from clogging the system. There is a purge valve for draining that allows a person to empty the water before moving the filter.

Pros
  • It can circulate up to 563-gallons of water each hour
  • The cannister height of 21-inches can fit under most aquarium stands
  • A monthly reminder indicates when it’s time for regular maintenance
Cons
  • This high-volume canister filter comes at a high price point

AZOO Aquarium Mignon Filter 60

AZOO Mignon Filter 60
  • Small compact design
  • Queit performance
  • Ease of maintenance

Last update on 2020-02-17 / Affiliate links / Images from Amazon Product Advertising API

While this unit is capable of working on tanks up to 10-gallons, it would be a good choice for tanks even smaller. This hanging filter can circulate nearly 16-gallons of water each hour.

 The filter takes up very space on the tank rim.   

The Mignon 60 offers decent biological and mechanical filtration, a good feature for such a compact design. Easy access allows a user to replace the cartridges quickly.

An adjustment knob provides concise water flow control, which can be critical in smaller tanks with a limited surface area.

 It may make vibrating noises at the highest settings.   

The clear plastic used for the product makes it less distracting. Starting filter media is included.

Pros
  • Can cycle smaller tank water columns two or three times an hour
  • An adjustment knob offers water flow control
Cons
  • There is not a lot of room for filter media in this small unit

AquaClear Power Filter 70

Aqua Clear - Fish Tank Filter - 40 to 70 Gallons - 110v
  • Re filtration system that offers superior contact time with filter media and energy efficient pump lowers operating costs
  • Quick and easy installation
  • Filtration volume is up to 7 times larger than comparable filters
  • Comes equipped with AquaClear Foam, Activated Carbon and BioMax and Cycle Guard for continuous biological filtration and superior water quality
  • 2 year warranty; Ideal for aquariums up to 70 gallons

Last update on 2020-02-17 / Affiliate links / Images from Amazon Product Advertising API

This hanging filter system is a good choice for those looking to use multiple media on a fish tank of 40 to 70-gallons in size. The filtration box can hold a good quantity of media. This is a great feature for users who want to mix materials for specific needs.

 The wheel produces very little noise while moving.   

It has a bottom-up design, which forces the media to travel through all of the loaded materials before re-entering the tank. Its wheel provides good aeration.

 The unit needs to be cleared of debris often to keep the wheel moving properly.   

All three media materials are included (Activated Carbon, AquaClear Foam, and BioMax/Cycle Guard).

Pros
  • This filter system can hold a lot of media product
  • Can circulate 300-gallons of water per hour
  • The bottom-up design forces water through all layers of filtration
Cons
  • The wheel box needs to be cleaned out regularly to prevent issues

Lustar – Hydro-Sponge IV Filter for Aquariums up to 80 Gallons

Sale
Aquarium Filter Hydro-Sponge IV by Lustar, for Aquariums up to 80 Gallons
  • Easy to clean, just rinse and squeeze in used aquarium water. Never use tap water
  • One inch diameter lift tube allows for high volume water flow and allows use of power head without adapters
  • Made from Proprietary Patented Sponge Foam for the highest mechanical debris capacity and bio capacity
  • The Hydro-Sponge traps waste particles, mechanically cleaning the water without trapping baby fish
  • Can be used in the vertical or horizontal position. Heavier base with a raised bottom

Last update on 2020-02-17 / Affiliate links / Images from Amazon Product Advertising API

The Hydro-Sponge IV provides a great home for bacteria colonies throughout the sponge material. It also presents a good barrier for catching debris as the water passes through it.

 This filter offers versatility for placement.   

The unit can be mounted vertically or horizontally, a nice design that allows a tank-keeper more options for placement. The base keeps the sponge off of the substrate, which can prevent a “dead space” from being created under the sponge.

 A separate pump will be required for operation.   

The sponge provides safety for smaller fish, making it a good choice for breeder or fry tanks.

Pros
  • It provides good biological/mechanical filtration for up to 80-gallons
  • The unit can be used horizontally or vertically
  • This filter provides a great home for good bacteria
Cons
  • The filter requires a pump to operate

Penn Plax Cascade 700 Canister Aquarium Filter

Cascade CCF2UL Canister Filter For Large Aquariums and Fish Tanks – Up To 65 Gallons, Filters 185 GPH
  • Quick easy push button self-primer
  • Independant 360 degree rotating valve caps
  • Sturdy tip-proof base
  • Flow rate cut-off valves adjust water flow

Last update on 2020-02-17 / Affiliate links / Images from Amazon Product Advertising API

For fish owners who want a silent running filter system, the Cascade may provide the silence they need. This due, in part, to the air-tight seals it employs. Attaching the tubes is easy to do, and preparing the filter for use takes only a few minutes. The base is wide enough to prevent the product from tipping over.

 The media baskets keep media separated.   

A cycle rate of 185-gallons each hour is capable of handling medium-sized water columns twice during that time. Its flow valves allow maintenance without having to remove other components from the aquarium.

The unit weighs 15-pounds when empty.

Its spray bar is long enough to disperse water evenly across a medium-sized aquarium. The product is covered by a three-year warranty and comes at a reasonable price point.

Pros
  • This canister filter is airtight and runs silently
  • The set-up on this canister is quick and simple
  • It comes with a three-year warranty
Cons
  • Caution must be exercised with the O-rings during maintenance

MarineLand Emperor Filter Systems, 400B

Marineland Emperor 400 Pro Series Bio-wheel Power Filter - Up to 80 gallon, Rite Size "E"
  • WITH ROTATING BIO-WHEEL: Patented Bio-Wheel technology provides excellent wet/dry biological filtration
  • MULTI-STAGE FILTRATION: Delivers mechanical, chemical and biological aquarium filtration to maintain a clean aquatic environment.
  • POWERFUL: Certified flow rate of 400 GPH in aquariums up to 80 gallons.
  • MARINELAND FILTRATION PRODUCTS: Count on Marineland brand for the most reliable, technically advanced aquariums and accessories on the market.
  • REPLACEMENT CARTRIDGES: Use with two Marineland Rite-Size E Filter Cartridges (purple label).

Last update on 2020-02-16 / Affiliate links / Images from Amazon Product Advertising API

The Emperor 400B may be an ideal choice for those looking for large volume water cleaning without a canister.

It can work well on aquariums ranging up to 80-gallons without overworking itself. This unit provides great biological filtration for a fish tank.

 The design incorporates a two-wheel system for operation.   

Two pumps are used to draw water through the filter cartridges and to spray the bio-wheels. There are two wheels located in the housing, a feature useful for those looking at getting the work of two hanging filters in one housing.

 Keep the filter clean: The wheels can begin to make noise without regular cleaning and maintenance.   

Both chemical and mechanical filtration is possible with the use of the cartridge system from MarineLand.

Pros
  • Can clean up to 400-gallons per hour
  • It uses two wheels for cleaning
  • There is a lot of room for filter media
Cons
  • The spray bars can become clogged unless they are cleaned often
  • The cartridges used in the system are a little pricey

The Winner…

Each of the seven products reviewed above offers great filtration with unique design features.

In the end, we feel that the MarineLand Emperor Filter Systems, 400B offers the best filtration for a variety of reasons. This hanging filter design employs two bio-wheels that provide a good exchange between air and water. This is something that canister filters cannot offer.

The flow control allows a user the ability to adjust the flow rate to a setting comfortable for the fish to swim in without generating too much water flow. This is something that submersible filters may struggle with. The two bio-wheels provide a great location for bacterial colonies to establish themselves. Some filters will be incapable of providing this type of biological filtration.

With the addition of filter cartridges, this unit can provide all three filtration media if desired. Some designs only employ one or two media types at a time. Finally, the hanging unit does not take up space inside of the tank itself. We hope you will give it a try!