The Best Filter for 20 Gallon Aquarium in 2021


What is the best filter for 20 gallon aquarium? How can you choose one that suits your needs? As there are many choices on the market, you can find it confusing to select from a wide range of filtration systems available.  For this reason, you might want to keep reading in the following for help!

In today’s guide, we’re discussing the top six products and their pros and cons.  In the process, you will be able to compare them better so that you can make an informed choice later.   If you’re ready, let us get started with the following best products reviews.

What is the Best Filter for 20 Gallon Aquarium in 2021

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Top 6 Best Filter for 20 Gallon Aquarium Reviews

1. Aqua Clear Fish Tank Filter for 20 Gallon Aquarium


If you have a 20-gallon tank and you want to keep it healthy, you should take a look at the Aqua Clear – Fish Tank Filter. This filtration system has thousands of positive feedbacks from its customers worldwide.    This filter is a power filter that work efficiently yet offers the versatility that you will appreciate.

The Aqua Clear filter is a hang-on filter, which can offer you a wide selection of water flow rates like for the 20-gallon tank and other popular sizes.  You can use it for a terrarium or aquarium that you might want to check out if you want a versatile filtration system.

It also has a great design, allowing for six times in terms of media volume as well as the longest contact time of water to media. It is the leading in the industry. When shopping around for a new filter, you should check out this feature to get more of your spending.


  • Complete selection of flow rates for different tanks
  • Unique design for longest water to media contact
  • Patented re-filtration system
  • Easy to install
  • 3-way filtration for optimal results


  • Struggles to refill after draining

2. Marineland Penguin Power Filter for 20 to 30 Gallon Fish Tank


The Marineland Penguin Power Filter is another top of the line choice in the category that you might want to take a look at if you are looking for a reliable and efficient system that can work for up to 30 gallons.

MarineLand is a reputable brand that’s been trusted worldwide for many years for its commitment to quality and performance of its fishkeeping products. One of its best offerings is this filtration system used to keep tanks clean for a healthy fish environment.

This filter offers three-stage filtration that includes chemical, mechanical and biological filtration. It also comes with a cartridge, making it ready out of the box.  In addition, this item comes with an activated carbon to ensure max efficiency.


  • Can filter up to 30 gallons
  • 3-stage filtration system
  • Patented BIO-Wheel
  • Black Diamond Premium Activated Carbon
  • Technically advanced accessory


  • Might need frequent replacement

3. Penn Plax Cascade Hang-on Aquarium Filter


The Penn Plax Aquarium Filter is another decent choice for an aquarium filter.  It is a hang-on type filtration system that works quietly in order to deliver up to 100 gallons of water per hour, keeping your marine or fresh aquarium clean for healthy fish.

It can help keep your tank water clear for a healthy living environment for your fish pets. The Bio-Falls Quad-Filtration system can offer an effective filtration for your tank.

Its filtration system makes use of innovation. It has anaerobic bacteria to remove nitrite and ammonia effectively, allowing for maximum tank oxygenation. It also involves activated carbon cartridge that’s able to get rid of toxins, chemicals, discoloration and odors, among other contaminants in your tank.


  • Quad Filtration System
  • Quietly operates
  • Adjustable flow knob
  • Removes harmful chemicals
  • Both freshwater and saltwater applications


  • Can be effective only for up to 20-gallon tanks

4. Aqueon QuietFlow Aquarium Power Filters


The Aqueon QuietFlow is an efficient and reliable filtration system designed for tanks 20 gallons in size. It can provide up to 100 GPH of water flow for effective filtration that work three ways. It can provide biological, chemical and mechanical filtration along with more assistance using filter pads.

This model also works with a self-priming operation. It only means that it can start working after a power interruption or cleaning, offering ease of use.  The filtration system also delivers your tank with certified flow rates for efficient water circulation.

This item also has an indicator light telling when to replace a clogged cartridge through monitoring the actual water levels. In addition, this filter also has an internal pump design, working to help us eliminate leaks and dampen noise.


  • Lifetime warranty
  • Certified flow rates
  • Internal pump design
  • Self-priming for ease of use
  • LED indicator light indicates cartridge change


  • LED indicator issue

5. Aqueon Quietflow E Internal Power Filter for 20 Gallon Aquarium


Check out the Aqueon Quietflow E Internal Power Filter when comparing your choices for an effective filtration for a 20-gallon tank.  It is by Aqueon, a reliable brand trusted by thousands of consumers worldwide. One of its finest products is the internal power filter, which works efficiently to keep your tank clean.

This model can offer biological, chemical and mechanical filtration for effective cleaning and health of your fish. In addition, this model works with a self-priming operation, running automatically after cleaning or a power outage.

The filter is also easy to install and use with just hanging clips or suction cups. That is one of the things that make the filter a choice among those who want easy installation.  More so, the Aqueon Quietflow E Internal Power Filter is backed by a limited lifetime warranty for added peace of mind.


  • Vertical orientation for efficient cleaning
  • Easy to install and use
  • Provides three-way filtration
  • Auto-start pump and self-priming
  • Limited Lifetime Warranty


  • Loud filter motor

6. Whisper In-Tank Filter with BioScrubber for 20 Gallon Aquariums


The Whisper In-Tank Filter is another choice among those who want to maintain the cleanliness of your fish tank.  With it, you can have peace of mind that your tank friends will remain healthy and happy in the clean living environment with which this tank can help you.

This filtration system is used designed to work effectively for tank with up to 20 gallons in size. You might want to check it out if you have this tank size and need efficient filtration. It comes with large filter cartridges, adding to its efficiency.

The Whisper In-Tank Filter can also offer quick installation with just the use of one or two suction cups or a hanger based on your placement. Overall, it is an effective filtration for terrariums and aquariums.


  • Large filter cartridges
  • Easy cleaning and maintenance
  • More affordable than others in the category
  • Comes with a BioScrubber
  • Convenient installation


  • Can fail working over time

Filter for 20 Gallon Aquarium Buying Guide

Whether you’re a new or a seasoned hobbyist or aquarist all over the world, you might want to check out a good 20-gallon filter for your tank.

It works perfectly well for this tank size, which is common as a species tank, starter tank or a breeding tank.  In order to keep it clean and promote a healthy living environment for your pet friends, you should find the right filtration with the following considerations.


You can find small sized filters for this relatively small tank.  Slim profiled filters are a great choice because it does not occupy much space. As remember, the bigger the filter the bigger the space it will occupy.

With this said, you could save more space to decorate your tank.  There will also be a bigger room for your fish to swim.  You might want to take a look at a hang on back filter or HOB because it offers space for your fish and decoration.


One of the most useful features of a filter is its self-priming operation. It only means working automatically back on after cleaning or a power interruption. Self-priming models do not require much attention as compared to those that still need to be primed in many cases.

Filtration process

You might want to check on filters that work thoroughly in order to ensure that it can keep your tank clean. In addition, you must select a filter that works for your schedule and at your time as well as consider water amount to process.


It’s essential when choosing a filter for your tank especially if you’re a busy owner that does not have much time to spend in keeping your tank clean.   It should also have a compact size but also has easy to disassemble parts for ease of cleaning.

These are only some of the things to consider when buying a 20-gallon tank filter that you should think about when weighing your options.

What is a Filter for 20 Gallon Aquarium?


A filter for the 20-galon tank is a filtration system that works by maintaining the cleanliness of the living environment of your marine or fresh tank.  It is essential to prevent you from cleaning the tank frequently and offer mechanical, biological and chemical filtration among select types. Nevertheless, every tank must have a filter for happy and healthy tank friends.

Types of Filter for 20 Gallon Aquarium

When shopping around for a 20-gallon tank filter, you might be interested to know what the types of these filters are. At the very least, there are many types of filters available on the market.   In the process, you can select the right kind of filter that works for your needs and preferences. Here is a brief overview of what to know about the matter.

Undergravel filter

This type is placed under the substrate or gravel; it does the cleanup job in this area. This filter cleans the tank mechanically by pulling the debris using its filter media. On the other hand, there are filters that can support biological filtration by allowing the bacteria on its exterior area.

Canister filter

It is pricier than others options are, but it is durable and quality. This filter can support three-way filtration, including chemical, biological and mechanical filtration. It is designed with a siphon tube into which it takes the water inside while also filtering it. This filter also has a separate tube that works by returning the water while controlling the current or water movement. With these features, you can realize that its price can be worth it.

Power filter

It is another filter type known as hang on back filter or HOB. It is the most common for many tanks on the market.   This filter might be one of those that you can typically see in many households. It works effectively and can offer versatility, as it can help in aspects that include chemical, mechanical and biological.

Why Do You Need Filter For 20 Gallon Aquarium?

A filtration system is what you need if you want to keep your tank clean. It works by sucking floating debris into its system providing mechanical filtration. Many of them also support biological filtration, allowing bacteria to colonize around it, as well as chemical filtration in select models.

But then, many of them offer all three ways of filtration, ensuring the cleanliness of your aquarium or terrarium. As a result, your fish, for instance, can prevent toxin and ammonia buildup in their bodies.

With that said, they could also avoid liver diseases and ammonia stress that can also be fatal for them. Without even saying, a 20-gallon tank filter is an essential part of your aquarium not to miss if you want all these benefits.

More so, a clean tank also means less maintenance on your part. You don’t have to clean it from time to time because an efficient filter does it for you. If you would like to take advantage of this feature for convenience, you should definitely take a look at one of the filters available for a 20-gallon tank.

There you have some of the reasons to have a 20-gallon aquarium filter that you want to get for your tank. Get started with the selection process using our guide earlier.

Frequently Asked QuestionsFAQs-fish

How does filter for 20 gallon aquarium work?

You might be wondering how this filter work for your aquarium or terrarium. At the very least, take note that filtration systems can work in different ways because each can have a specialized type of filtration to do – like mechanical, chemical and biological; some filters can provide all these three.

Biological filtration means your tank is maximizing the good bacteria thriving in your tank.  They can help in keeping the tank clean because they break down byproducts of live plants and little fishes and turn them into harmless ones.

It happens using the nitrogen cycle. This type of filtration supports beneficial bacteria by giving them a spot where they can colonize.

Mechanical filtration is also called physical cleanup of fish corpses and leftover feed. They are forced into the filter media to clean the tank.

On the other hand, the chemical filtration works by removing toxic elements and compounds from your tank using aquarium chemicals and chemical filters.   With it, you can have peace of mind that the water quality of your tank is supportive to the health of your pet fish.   You can also rely on it for helping you reduce the frequency when you have to clean the tank.

There you have some of the things to know on how the filter works to clean your aquarium and help maintain a healthy living environment for your pets. With it, you can be sure that your fish will be happy and healthy and that you don’t have to clean your tank very often.

What size carbon filter for 20 gallon aquarium?

You can find models available for filtering 20-gallon tanks or aquariums. Get started with the selection process using the above reviews.

Where to buy filter for 20 gallon aquarium?

Places to buy include fish supplies and pet supplies stores. Online, you can buy them from reputable sites like


Finding the a 20 gallon aquarium filter can be easy and less time consuming if you know what to look for when choosing among different products in the category.

Again, compare filters based on their size, operation, filtration process and maintenance, to name some. Find out which among those filters can work well according to your desired features, including three-way filtration, self-priming and ease of cleaning, too.

To get started with the selection process, you might want to refer to the above reviews. Using this information, you can buy the best filter for 20 gallon aquarium and have a more rewarding experience in the process.



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