The Best Aquarium Filters: Mechanical, Biological & Chemical Filtration

Of all the many aquarium supplies, aquarium filters are the most vital piece of equipment. Filters keep the fish tank’s water clean, clear, and healthy. Here’s everything you need to know about choosing the right filter for your aquarium.

Best Aquarium Filters Reviews

These are the best aquarium filters:

OASE Indoor Aquatics BioMaster Thermo

The OASE Indoor Aquatics BioMaster Thermo has a sleek and attractive design. Not only is it an excellent filter for your fish tank, but it also has a built-in heater.

It has a prefilter module that you spin out of the canister to rinse and reuse again. It also comes with intake and outlet, suction cups, a spray bar, activated carbon pads, and bio media. It uses a 4 stage filtration mechanism ( biological, mechanical, chemical, and prefiltration) to keep the water safe for fish.


  • Very quiet
  • Easy to prime
  • Separate, removable prefilter unit
  • Integrated, removable heater
  • Large media trays
  • Sturdy handle
  • Long input/output hose
  • 360° rotatable hose connection nozzles
  • Flow controllable hose adapters
  • Mounting components for using the heater external to the filter
  • Durable


  • Potential points for seal failure
  • User manual errors
  • Confusing component names
  • A small amount of plastic bio media included

Marineland Magniflow Canister Filter for Aquariums

This Marineland aquarium canister filter has bio-filter balls and ceramic rings that produce to support good bacteria growth. The black diamond carbon gets rid of odors and other impurities in the water, while the filter foam pads catch dirt and debris.


  • Suitable for aquariums up to 100 gallons
  • A fast and powerful filtration system
  • A quick auto prime feature
  • Easy to install
  • Durable
  • Comes with media filters


  • Potential leakage issues
  • Bulky

Fluvial C Power Aquarium Canister Filter

The Fluval C Power Filter is a 5-stage filtration system for aquariums between 40-70 gallons. It filters up to 264 gallons of water per hour. There’s a cleaning indicator that lets you know when it’s time to clean the polyfoam. It utilizes a clip-on filter for easy and quick maintenance.


  • Available in many sizes
  • High hourly filtration capabilities
  • 5-stage filtration
  • Easy to mount and set up


  • Gets loud after prolonged use
  • Some parts are not durable
  • Needs space behind the tank to set up

Sunsun Pro Canister Filter

The Sunsun Pro is a 4-stage canister filter that has three filter baskets to capture debris. It uses fine and coarse filter pads as well as activated carbon in a pouch.


  • Easy to setup
  • Built-in a UV sterilizer
  • Quiet
  • Filters up to 535 gallons per hour


  • Filter motors not durable

API Nexx Filter

The API Nexx Canister Filter has many high-quality plastic components. It has a modular set-up where you can add another extension for a larger tank. Add one Nexx filter for up to 110 gallons, add two for 165 gallons. The filter has a Bio-Chem Zorb, an activated carbon + high-performance adsorption resin. Bio-Chem Stars; a porous plastic biological filter.


  • Durable
  • No priming needed
  • Quiet operation
  • Easy to clean and maintain without unplugging
  • Large media trays with media included
  • Great value for the price


  • Stiff tubbing can be difficult to place into the disconnect valve
  • Multiple pieces that you have to connect
  • Not enough media included (additional purchase necessary)

EHEIM Classic External Canister Filter

The Eheim Classic is a simple aquarium canister filter with essential functions. There’s no media basket, and the filtration material is inside the canister. There’s also a spray bar, inlet pipe, hose, and other installation accessories, filter media (EHEIM Mech & Substrat Pro), and valves.


  • Silent operation
  • Easy to install
  • An effective water filtration system
  • Low energy consumption


  • Replacement parts hard to find
  • The impeller is prone to breakage

Hydor Professional External Canister Filter

The Hydor professional filter has a biological, mechanical, and chemical filtration system. So, the water in your aquarium is always fresh and clear. Other additions are media baskets with mechanical filter pads and biological filtration media.


  • Easy to set up
  • Safety lock system
  • Easy to use and clean
  • Powerful flow rate
  • Easy priming system


  • Potential leakage issues when disconnecting valves


Aqueon QuietFlow HOB Filter (Power Filter)

The Aqueon QuietFlow hang-on-back filter has four filtration stages (mechanical, biological, chemical, and specialty filter pad). It has a lifetime warranty, easy to set up, and alerts you when the filter is ready for a change. It’s very quiet yet effective. But, if you keep small fish, you need a pre-filter sponge.


  • Easy to set up
  • Self-priming feature
  • LED light to tell when the filter pad needs changing.
  • Quiet


  • Pre-filter sponge is needed for the intake tube if you have small fish.
  • Small filter so it has less space for media.
  • Larger models are slightly louder than the smaller ones.

Penn Plax Cascade Hang-on Aquarium Filter

The Penn Plax Cascade filter has different sizes for fish tanks between 5 to 100 gallons. It offers three stages of filtration: biological, chemical, and mechanical. It is easy to set up, affordable and has a 3-year warranty.


  • It has a large tank, which provides more extended use before you need to replace the filter.
  • The materials used to build the filter are durable.
  • It’s easy to set up.
  • It comes with bio-sponges, bio-floss, activated carbon, etc.


  • The filter makes noticeable noise when running.

Marineland Power Filter

The Marineland power filter is easy to set up, cheap and has options for a variety of tank sizes up to 70-gallons. But, it can be a bit louder than other filters on the list. It has all three stages of filtration.


  • Quiet
  • The filter is easy to prime
  • Affordable


  • Not as durable as other options on the list.

Fluval HOB Filter

There are three variations of this hang-on-back aquarium filter:

  • The C2 is great for tanks between 10 gallons and 30 gallons. The flow rate is 119 gallons per hour.
  • The C3 works best with fish tanks between 20 and 50 gallons and has a flow rate of 153 gallons per hour.
  • The C4 is best for tanks that are 40 to 70 gallons and it has a flow rate of 264 gallons per hour.

Simple Aquarium Sponge Filter

Here’s a simple sponge filter that provides basic mechanical filtration and biological filtration.

Lee’s Premium Undergravel Filter

Here’s a good under gravel filter that overs all three stages of filtration.

What Are Aquarium Filters?

Aquarium filters are one of the most critical components of both freshwater and marine fish tanks. Aquarium filters remove physical and soluble chemical waste from aquariums, thus making maintenance more manageable, providing a healthier ecosystem for plants and aquatic animals.

Why You Need An Aquarium Filter?

You need a filter in your aquarium to keep the water in your fish tank clean. Filtration removes debris and toxic chemicals like ammonia and nitrite.

Filters can also help oxygenate the water through surface agitation. You should use an aquarium filter to reduce the risk of disease in fish and plants and to help maintain a clean and healthy environment.

Types of Aquarium Filtration

There are different methods of filtration: mechanical filtration, biological filtration, and chemical filtration. Some filters use all three or a combination of two. Others only offer one kind of filtration.


  1. Mechanical filtration: water passes through a solid barrier to remove solids.
  2. Biological filtration: nitrifying bacteria build up to convert toxic compounds like ammonia and nitrites into less harmful nitrates (remove with partial water changes).
  3. Chemical filtration: uses media such as activated carbon to get rid of impurities.

Mechanical Filtration

Mechanical filtration removes uneaten food and other debris from the water. As water from the aquarium passes through the filter, it removes debris like uneaten food. Most mechanical filters include filter cartridges, sponges, and fibrous pads. Mechanical filtration occurs first in a fish tank filter that offers 3-stage filtration.

Biological Filtration

Biological filtration gets rid of ammonia, which is toxic to fish. It’s crucial that our fish tanks have some form of biological filtration. The way it works is that colonies of nitrifying bacteria grow on the biological filter and then, in turn, convert Ammonia into Nitrite, and then Nitrite into Nitrate as filtered water passes through. To prevent nitrate build-up, perform weekly partial water changes. Biological filtration occurs after mechanical filtration.

Chemical Filtration

Chemical filtration helps to remove heavy metals and other impurities. Most use activated carbon and filtering resins to adsorb/absorb impurities. For example, one can use chemical filtration to remove a build-up of fish medicine.


Types Of Aquarium Filters

The main types of aquarium filters are:

  • External Canister Filters
  • Hang on back (HOB) Power Filters
  • Sponge Filters
  • Under-gravel Filters

External Canister Filters

Canister filters are external filters with two tubes that connect the filter to the tank. An intake tube removes dirty water from the tank and brings it to the filter. The water then goes through the filtration process before going back into the tank through the second tube. One can set up a canister filter to provide all three stages of filtration; mechanical, biological, and chemical.

Best External Canister Filters

Hang on back (HOB) Power Filters

A hang on back (HOB) filter is a type of filter that hangs on the back of the tank. So, it’s an external filter, but not it is not as big as canister filters. Their size makes them suitable for a wider variety of aquariums, and they can use all three types of filtration.

A water intake tube takes water from the tank to the filter. Filtration occurs inside the filter. The filtered water then returns to the tank through tubes that create a waterfall-like flow.

Best HOB Power Filters

Sponge Filters

Sponge filters are simple and easy to set up. These filters submerge in the water and water passes through the sponge via an air stone or water pump. Most beginner aquarium kits have sponge filters. But, you usually need a more powerful filtration system to work best for most tanks.

Best Sponge Filters

Under-gravel Filters

Undergravel filters are very effective, but regular cleaning is a must. They are not best for planted aquariums as they slow down the plants’ growth.

Best Under Gravel Fish Tank Filters

Air-driven Internal Fish Tank Filter

Air-driven internal filters are small. If you own nano aquariums, these types of filters are best. Though small, air-driven filters do an excellent job at keeping small fish in small aquariums healthy.

Best Air-driven Internal Fish Tank Filters

Benefits Of Using An Aquarium Filter

  • Less stressful for fish – fish tank filters reduce the frequency at which you need to physically clean your tank.
  • Less maintenance – helps reduce waste/keep water clear and clean (in addition to bottom feeders / UV Lights).
  •  Removes excess food that your fish don’t eat, reducing the risk of ammonia spikes, overfeeding, algal blooms.

How To Choose An Aquarium Filter?

The main things to consider when buying an aquarium filter are:

Aquarium Tank Size

The size of your fish tank will limit the kind of filter you can use. For example, not all fish tank filters work with all sizes of fish tanks. When buying a filter for your aquarium, always check the recommended tank size. If you’re buying online, it’s usually in the description. If you’re buying in a store, ask the store clerk for help.

Water Flow Rate

The faster the water flow rate of your aquarium filter, the more water it can clean per hour. Depending on the size of the tank, always choose the filter with a higher water flow rate.

Read Reviews

If you’re not sure about a filter or think that the features are too good to be true, look for reviews online. An excellent place to start is Amazon. Find the product and look through the reviews to get an idea of what you’re about to buy. You might even find some useful tips in the review section.


While each filter is different, they all help to keep your aquarium clean. Choose an aquarium filter that best suits your setup taking into consideration the size of your tank and space around the tank. Be sure that the filter can fit your aquarium. Any of the above best fish tank filter systems can help keep your aquarium water clean and clear depending on your needs.

Before you go, read our article on cleaning a filter in a fish tank—an essential part of maintaining a healthy ecosystem.