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Best Filters For 20-Gallon Fish Tank And Aquariums In 2021 – Top 6 Rated Reviews

We know how much of a pain it can be to shop around online for aquarium products. There are tons of products all claiming to be the filter out there and reading through them all is mind-numbing. To help you out we have found some of the best filters for 20–gallon aquariums.

We have picked out 6 great filters that will work perfectly in smaller tanks. Below, we go over each model so you can choose which filter will work best for your home. We even listed out the cons of each item so that you know the potential downsides before purchase.

Best Filters For 20-Gallon Fish Tank And Aquariums

The 6 Best Filters For 20-Gallon Aquariums In 2021 Review

1 Aqua Clear – Fish Tank Filter – 5 to 20 Gallons – 110v

Aqua Clear Fish Tank Filter is great for people who own smaller aquariums. This is the perfect starter kit for anyone who needs to add in a filter to their tank. This product even has its own special line of accessories to help the filter run smoothly for years to come.

This has a water output rate of 100 gallons of water per minute. This is a three-stage filter using biological, mechanical, and chemical filtration. In addition, you can control the flow of water for this system. This makes it perfect for tanks with fish who prefer a calmer environment.

This filter measures 4.5 x 7 x 6.5 inches and weighs 1.4 pounds. This filter is made to be an energy efficient model to keep it’s operation low cost. It also comes with a 2-year warranty in case anything happens to your purchase. Just notify the company for a replacement.

With this product, you will receive AquaClear Foam, Activated Carbon and BioMax with cycle guard. Be sure to regularly clean this model of filter to keep it working properly. You can also purchase AquaClear media that will fit perfectly into your new filter

There are a few downsides to this product, however. This filter doesn’t have a very strong flow rate which may disappoint some. It can also be a very noisy model, making it hard to keep in your bedroom.

Aqua Clear - Fish Tank Filter - 5 to 20 Gallons - 110v
Our rating:3.9 out of 5 stars (3.9 / 5)

  • Easy To Set-Up
  • Three-Stage Filtration
  • Noisey
  • Flow Rate

2 Fluval C Power Filter

The Fluval C Power Filter is perfect for small tanks or lazy fish. This is the C2 model of Fluval filters that are perfect for 20-gallon tanks. It even comes with everything you need to get started making it a perfect choice for those who have never used a filter before.

This filter has a flow rate of 119 gallons of water per hour and works well up to 30 gallons of water. If you want something a little stronger then you can go with the C3 which is perfect for a 20-gallon tank as well. The C3 has a slightly stronger flow rate at 153 gallons of water per hour.

This filter measures 4.5 x 6 x 8 inches and weighs 1.9 pounds. It even features a ceramic heater core to make sure that the heat is evenly dispersed in the filter. It also features a cleaning indicator so you will know when you need to rinse it your poly foam.

With this filter, you will get chemical, mechanical, and biological media to get you started. This filter uses 5-stages of filtration to ensure that your water is crystal clear. All you need to do is ensure that the filter is properly cleaned and change out the media when needed.

So, what are this filters downsides? This filter is pretty noisy and just doesn’t sound that great when it’s running. The internal parts of the filter also have a tendency to break or need replacement quite often. This can lead to the filter turning off out of nowhere.

Fluval C Power Filter
Our rating:3.7 out of 5 stars (3.7 / 5)

  • Two Models To Choose From
  • Powerful Filtration
  • Ceramic Heater
  • Internal Parts Can Break Unexpectedly
  • Unpleasant Noise

3 Marina Power Filter

The Marina Power Filter is simple and easy to use accessory perfect for beginners. The Marina is one of the best filters for 20-gallon aquariums out there. It’s made to be easy to work with so you won’t have to waste your time trying to get it set-up.

This filter has a water flow rate of 92 gallons of water per hour. While this may be one of the lower ratings on this list it still does a wonderful job of keeping your tank clean. This is, of course, all at an inexpensive rate so that just about anyone can invest in this model.

This filter measures an ultra-thin 3.8 x 11.5 x 6.4 inches and weighs just one pound. It’s also self-priming to keep you from having to do any extra work. The best part is you can control the water flow. This makes this filter perfect for fish who need a calm environment.

With this filter, you will receive everything you need to get started. Included with your purchase is a 2 Bio-Carb and 2 Bio-Clear with both cartridges containing Ceramitek. All you need to do is make sure that regular cleaning takes place to keep it running smoothly.

Like with most products the Marina does have some downsides. The filter may be small, but it makes a lot of noise that is rather unpleasant. You will also find yourself changing out the media a lot. This is because the strips of media you use incredibly thin.

Marina Power Filter
Our rating:4.2 out of 5 stars (4.2 / 5)

  • Slim Design
  • Easy to Get Going
  • Media Needs Frequent Changing
  • Loud

4 Penn Plax Cascade Canister Filter

The Penn Plax Cascade Canister Filter is a small, but powerful product that you will simply love. The company behind this filter strives to make sure you are completely satisfied with your purchase. You are even covered by a gracious warranty from the moment it arrives.

The filter has an output rate of 115 gallons of water per minute and is perfect for up to 30-gallons of water. This filter uses rotation if valves similar to what you would find in most pool pumps. This helps create a powerful cleaning cycle that will leave your water crystal clear.

This filter measures 13.5 x 11.5 x 9 inches and is a heavier model weighing in at 9 pounds. This filter even has a valve to help you adjust the flow of water. These valves are easy to use making the process of controlling your tank easier than ever before.

With this filter you will receive, large filter trays, start-up filter media & input/output tubing. This provides everything that you need to set yore new tank accessory up and running. This filter features a push buttons primer that you will need to use when starting up.

There are a few cons to this model. This filter may have a problem with making a loud rattling sound. This can be unpleasant and may interrupt the serenity of your set-up. Other than that this filter functions perfectly as long as you clean it regularly.

Penn Plax Cascade Canister Filter
Our rating:3.8 out of 5 stars (3.8 / 5)

  • Large Media Basket
  • Powerful Filter
  • 3-Year Warranty
  • Can Make a Rattling Noise

5 The Best Marineland Penguin Power Aquarium Filter, 10 to 20-Gallon, 100 GPH, Fish Tank

The Best Marineland Penguin Power Aquarium Filter is another perfect choice for small tanks. This filter has all the power you need to help keep your water clear and your fish happy. It uses three stages of filtration to give you clean water all the time.

Unlike most filters, the flow rate of the Marineland is certified 100 gallons of water per hour. This filter is guaranteed to give you the water flow you are looking for. It even uses the Rite-Size filter to ensure that everyone you use of a perfect fit for this filter.

This filter measures 8.2 x 5.5 x 5.4 inches and is a light 1.52 pounds. This filter uses a three-stage filtration process to make sure your tank gets clean. The filter is also easy to have up and running in your tank in a very short period of time.

With your purchase, you will receive a Rite-Size cartridge so that you can get started immediately. There is even a larger sized rated from 20 to 30 gallons with a stronger flow rate. Like this model the larger model also has its gallons per hour certified.

This model does come with a few downsides. This filter can unexpectedly stop working due to failing internal parts. This can also make the filter rather noisy. The filters parts are replaceable, but it can be a hassle to take apart and put back together.

The Best Marineland Penguin Power Aquarium Filter, 10 to 20-Gallon, 100 GPH, Fish Tank
Our rating:3.6 out of 5 stars (3.6 / 5)

  • Certified GPD Rate
  • Cleans Wonderfully
  • Faulty Parts

6 Tetra Whisper In-Tank Filter with BioScrubber for Aquariums

The Tetra Whisper In-Tank Filter with BioScrubber for Aquariums is a powerful filter. It is great for beginners and one of the best filters for a 20-gallon aquarium. It even runs quietly so that you can keep it in any room of the house without noticing it’s there.

This product has an output rate of 80 gallons of water per hour. This is a model of filter that actually goes inside of your tank. This helps to keep the noise down by muffling the sound. This filter can even function in as little as 2 inches of water.

This filter measures 4.9 x 5.4 x 10.2 inches and weighs just 1.45 pounds. This filter was designed to work in aquariums 20-gallons of size and smaller. This filter uses two suction cups that come included to let you place it on your tank anywhere you wish.

With this filter, you will also get a pre-assembled Whisper Bio-Bag to get you started. This filter also has a removable bottom for easy cleaning. This makes the filter much less of a hassle to take care of when doing maintenance.

There are some cons to owning this filter. This filter has some trouble starting up sometimes. It also has limited space for adding in medium to your tank. This can make finding filter cartridges that fit a little bit of a hassle.

Tetra Whisper In-Tank Filter with BioScrubber for Aquariums
Our rating:3.7 out of 5 stars (3.7 / 5)

  • Runs Quiet
  • Goes Inside of Your Tank
  • Limited Media Space
  • Start-up Trouble

Picking Out Your Filter

Now that you’ve seen the great options we have listed above you may already have a favorite picked out. These are some of the best filters for 20-gallon aquariums. While each of them has their ups and downs they are all great products overall.

Remember to look into how much water flow your fish prefer. You will also want to decide whether you are ok with a noisy filter or not. Make sure to closely look at both the pros and cons of each item before you make your final decision.

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