5 Best 20-Gallon Fish Tanks – Enough Space for Your Favorite Fish

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Last updatedLast updated: December 19, 2021
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Looking for a new aquarium to add to your home? Are you possibly adding another one to your growing collection? You have come to the right place! Read on as we compare the top five best 20-gallon fish aquariums available!

We have reviewed the best 20-gallon fish tanks on the market. We compared their size, their weight, the accessories that come with them, and their overall design. We chose the ones that had the most and best customer reviews of any on the market. What we ended up with is what we consider the top 5, 20-gallon fish tanks available. There are many things to consider when buying an aquarium, and we have taken the guesswork out of the equation for you! You might ask yourself, “What size or shape should I get?” or “What is the best material to look for?” “Is it hard to maintain and clean?”. In this review, we will answer those questions and many more. So, if you are ready to buy the best 20-gallon tank on the market, keep reading, and you will find the perfect fit for your needs!

Top 5 20-Gallon Fish Tanks Review 2022


GloFish Aquarium KitEditor’s Choice

  • Material: glass
  • Weight: 34.15 lbs.
  • Dimensions: 24.2 x 12.5 x 16.2 inches
  • Accessories: LED light; filtration

More features: colorful neon display; easy to set up

This GloFish Aquarium kit comes with everything you need to get started immediately! Including the pure glass tank, two plant multipacks, one GloFish yellow anemone, LED hood and more! This makes it one of the best tropical fish aquariums on the market!

What stands out? We like that it comes with everything you need to get started right away. The company also offers plenty of accessories and add-ons for all your needs.

What cons did we manage to find? While not necessary, it would be nice to see the unit come with a lid. While you can replace the whole LED light, the bulb itself is not changeable. Here, the company recommends buying an aftermarket LED to replace the factory component.


Tetra AquariumPremium Pick

  • Material: glass
  • Weight: 34.3 lbs.
  • Dimensions: 27.88 x 16.13 x 20.38 inches
  • Accessories: LED lighting; decor

More features: made in the USA; scratch-resistant

The Tetra 20-gallon Fish Tank Kit is one of the best available on the market today. It has clean lines and a pure glass body that make it solid and nice to look at an aquarium. It comes equipped with an LED hood and Whisper filter.

What stands out? We loved that it comes with everything you need to get started, including some higher-end accessories. These include the Whisper filter, a great heating element, and natural looking artificial plants that help keep your new fish calm.

What cons did we manage to find? We thought that even for a premium brand, the price was a bit high. The filter needs replaced often, and because it’s an upgraded version, this will cost slightly more per year to operate.


Tetra ColorFusion AquariumBest Filter

  • Material: glass
  • Weight: 34,35 lbs.
  • Dimensions: 27.88 x 16.13 x 20.38 inches
  • Accessories: LED lighting; décor; UL heater; filter

More features: customizable light

This Tetra ColorFusion Aquarium is a great choice for those new to aquariums, or those looking to gain another for their growing collection. Modern style and changing LED lights make it great hit for all age groups. The special Tetra plants will appear to change before your eyes under the LED lighting.

What stands out? We love the modern styling and features of this aquarium. It is made of solid glass with extra corner support on the bottom edges, reducing the chances of breakage. It comes with accessories that are meant to work together, such as the LED and the special plants.

What cons did we manage to find? The filter could be a better model, such as one that may last longer. It could come with a solid lid that is part of the hood, to make removal easier.


Aqueon AquariumVersatile

  • Material: glass
  • Weight: 22 lbs.
  • Dimensions: 30.25 x 12.5 x 12.75 inches
  • Accessories: none

More features: silicon edges; for both fresh and saltwater

This Aqueon made 20-gallon long tank is great for those looking for just the tank, no included accessories. It is great for saltwater or freshwater, with solid glass body and silicone sealed seams. This makes it one of the best standalone 20-gallon fish tanks available.

What makes it stand out? We liked that it has a solid glass body and is suitable for freshwater and saltwater. It has quality silicone sealed seams that are guaranteed not to leak.

Which disadvantages must you keep in mind? We would like to the aquarium come with a lid, or at least a hood. Also, it would be nice to come with an optional background, that the end user could apply if they wanted.

  • Material: acryl
  • Weight: 20 lbs.
  • Dimensions: 24 x 13 x 16 inches
  • Accessories: reflector; electrical light fixture

More features: safe for salt and freshwater; strong construction; durable

This SeaClear Acrylic Aquarium Combo Set in the one of the best 20-gallon aquariums on the market. It comes ready to put gravel, water, and fish in and set back and enjoy the tranquility. The extra clear acrylic, that it is clearer than glass, will bring a new life to the whatever you put inside. Acrylic is twice as strong as glass, while only weighing half the weight!

What are its best features? We love the extra clear, solid body design. We like that it is suitable for freshwater and saltwater. We love that its acrylic design only weighs half the weight of a normal glass aquarium of the same capacity.

What could be improved? It would be nice to have a plastic lid or hood rather than the acrylic, which could warp. Does not come with any plants.

Things to Consider

Today, we have reviewed the top 20-gallon fish aquariums on the market. These are the best options on the market that come with the best and most customer reviews. We compared their size, their weight, the accessories that come with them, and their overall design. What we ended up with is what we consider the top 5 best 20-gallon fish tanks available. There are a few things to always consider if you do go with some different choices than the ones that we picked.

Advantages of a 20-gallon fish tank

There are many advantages to buying a 20-gallon tank versus any smaller size. It is a great size for any size of home. You can pick a great local spot and have it as the focal point of any room! All you need to do is have ample space around the fish tank so it doesn’t get knocked over. It will need the proper cleaning and maintenance, so take this into consideration when deciding where to place it.

This size is large enough to host a number of different species at one time. All you need to make sure is that they are either saltwater or all freshwater, and you will be good to go! This is also big enough to house a number of real plants if you should decide to go that route instead of the fake plants that most come with. Real plants and certain fish can make a tank run cleaner for a longer period of time, so this a viable option to consider.

You do not have to clean a 20-gallon tank as often as a smaller capacity tank. This means much more time to enjoy the environment you have created! While cleaning is not that hard of a job, it does consume some time. And it is required! There are some things you can do to minimize the number of times you have to clean, including certain plants and certain species of fish that will work together to keep the tank cleaner!

You will get less food waste because you can have more fish for the available space. Wasted food can cause a lot of problems for a fish tank, including causing the filter to need to be changed more often, causing the water to need to be changed more often, and causing the condition of the fish to deteriorate. The more often that you have the clean the tank, the more likely the fish will stay stressed out and not enjoy the environment you have made them, possibly even becoming hostile with them.

You can have some fish that are not suited well to the smaller tanks. This means even more options and more variety that you have available to you! There are all kinds of exotic fish that are available to us, especially if you choose to go with a saltwater tank. This also means that you can get more of one kind of fish, even if they can be territorial as the bigger tank will give ample space for them to have their own territory.

Features to consider before you buy a 20-gallon fish tank

5 Best 20-Gallon Fish Tanks - Enough Space for Your Favorite Fish

If this is your first time buying a 20-gallon fish tank, there are some key features you should look for when buying one. Do not be afraid of all the options out there. That is why we made this list! However, if you choose to go with another choice, keep some important features in mind.


Glass or acrylic is the best choice. Glass is the industry standard. However, acrylic is becoming more popular. Both of these are quality choices for any fish tank. Almost all of our picks are made of solid glass and will last a lifetime, save one. The SeaClear Acrylic Combo set is made purely of acrylic. But don’t let this steer you away. It is both stronger and lighter than its glass counterparts.


The average glass, 20-gallon fish tank weighs in at 225 pounds when filled with water. This is no small weight, so make sure you have adequate support. If you look at our Editor’s Choice, the GloFish Aquarium Kit, it weighs just over 34 pounds. However, if you look at the SeaClear Acrylic Combo set, it comes in at only 20 pounds!


24 x 12 x 20 inches is the standard size for a 20-gallon fish tank. There are other sizes available in the custom market. You could get almost any size and any shape you would like built, but all of our choices fit the standard size. The Tetra ColorFusion Aquarium, our third choice, comes in one of the industry standards, 27.88 x 16.13 x 20.38 inches. While one of our choices, the Aequen Aquarium, comes in at 30.25 x 12.5 x 12.75 inches, which is slightly wider than we normally see.


There are many accessories, including filters, lids, LED lights, plants, backgrounds, heaters, gravel, food, hoods, seasonal decorations, and alternating fish.

There are so many options out there that are available for purchase that you could never get tired of changing out what is inside your tank.
Our Editor’s Choice, the GloFish Aquarium, comes with the highest number of accessories when purchased. However, this should not stop you from searching for extra accessories!


The square design is what you typically get with a 20-gallon fish tank. Some custom companies will build special shapes. All of our picks come in the standard shape, but some are slightly wider, while some are slightly taller. They will all still hold the same amount of water when filled with water. You can add more tanks to your collection instead of trying to get a custom design made as this is often cheaper and more efficient in the long term than going for the custom-made tank.


Setting up an aquarium is an amazingly simple process. Every new aquarium kit will come with detailed instructions on how to properly set up your new aquarium. If you still have any kind of difficulties in doing this, you can watch any number of YouTube videos that will walk you through the process, step by step. In just a few simple steps and patience, you will be enjoying the aquarium of your dreams! You simply pick the spot for your tank, clean it as directed, add your gravel, and water. You then install all your equipment and add any plants and decorations. Finally, you cycle the water as directed and add your fish, and you are done! This process could not be any easier and does not take very much time at all. You will soon be enjoying your new 20-gallon fish tank and showing it off to all your friends and family!

Cleaning your fish tank is also a very simple and relatively short times affair. You only need to do a few simple steps to make sure your tank and all its inhabitants stay as healthy and happy as possible! If you notice that it is getting time to clean your tank, you need to get a few things ready in advance. You need a tank vacuum designed specifically for the gravel in the bottom of your tank, a large bucket, an algae scraper, clean towels, and some prepared water to return to the tank when finished. You want to leave some of the water in the tank, as there are microbial colonies that are important to the ecosystem of your tank living there. Once you have most of the water out, you want to scrub the walls and lid down, wash it, then vacuum the bottom of the tank. The fill with the prepared water, change your filters, and you are all set.

Our Verdict

Hopefully, this guide has given you all the information that you need to purchase the best 20-gallon aquarium available on the market today! From the Editor’s Choice GloFish with all the extras for a great price, down to our Best Value SeaClear Acrylic with its clearer than glass walls, our Premium Pick of the Tetra 20-Gallon Fish Tank has all the upgraded features available or the Tetra ColorFusion Aquarium, which is one of the best choices on the market for all-around features and accessories. The Aqueon Aquarium is one of the best choices available for those looking just for a replacement tank or possibly a tank to add to their collection. These are the best options on the market, with the highest customer reviews of equivalent products. With these choices and their specifications and accessories, we trust that you will buy the absolutely best 20-gallon aquarium that perfectly fits your needs and your style.

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