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9 Best 20-Gallon Aquariums – Reviews & Top Picks

While keeping fish is a fun and rewarding pastime, getting started can be difficult if you don't know what supplies you need.

The first thing you need to do is choose an aquarium; Newbies to the aquarium should choose a 20-gallon tank.

Both complete kits and bare tanks (without accessories like lights, filters or heaters) are available, but it's important to do some research before deciding on a supplier.

BestForPets (bestforpets.org) reviewed all the options available and selected its best 20 gallon aquarium.

A reliable aquarium for your home can be found by reading our reviews and following our buyer's guide.

How to Choose the Finest 20-Gallon Aquarium as a Buyer

If you’re still unsure about which aquarium is best for your needs after reading through our evaluations, consider these options.

Kit for Newbies or Empty Tank?

With a starter kit, you can save the hassle of searching for individual components by having everything you need in one convenient package.

You can save money by ordering a kit in several situations. For less than $200, it seems like you could have a tank, hood and filter, heater, and LED light.

However, the low cost of certain kits may mask the fact that they may not contain the finest components available. While the kits we chose as the best had fewer issues than the others, you should still be prepared to replace a part when you buy a package.

Though the Tetra ColorFusion aquarium (#4) is widely regarded as a top-notch aquarium kit, several buyers reported being disturbed by the loud whirring of the filter.

There were no structural flaws, but a bedroom aquarium with a loud filtration may be an annoyance. It’s also important to think about whether you’ll actually use all the components of the kit to properly care for your fish. There is no use in getting a kit that includes a heater if your fish do not require warm water.

When you start with a tank and buy the components individually, you can spend more money, but you also have more options when it comes to aquarium filters, lighting, decorations, and supplies.

Higher initial costs for high-quality components may be offset by the reduced need to often replace broken machinery.

Specifying Fish for 20-Gallon Aquariums

Fish selection is tricky in a 20-gallon tank, but is ideal for beginners. Always find out how big your potential fish will get before buying it.

Although goldfish are more resilient than many other aquarium fish, this does not guarantee they will thrive in the confined spaces of a bowl or a small tank.

Goldfish may grow to be over 12 inches in length, so a 20-gallon tank is too little until they reach adulthood. Ideally, a 75-gallon tank should be used for mature goldfish. The following are examples of species that can be kept in a 20-gallon aquarium:

  • Light-up tetras
  • Guppies
  • Single Betta Fish
  • Smooth fish
  • Danios


While decorative elements like plants, pebbles, and driftwood can enhance the aesthetic appeal of an aquarium, it’s easy to go overboard. While some fish are always active, others like to float invisibly behind cover such as plants.

It’s best to keep the decorations to a minimum to make room for fast swimmers rather than hiders.

If you’re just getting started with fish keeping, you could have more luck at first using fake plants than than actual ones.

Artificial plants may not be as visually appealing as their natural counterparts, but they are more resilient to changes in water chemistry. Adding live plants to an aquarium is a good idea after you’ve kept fish for a while.

Visitor Aquarium Maintenance

If you want your fish to grow and live for years, you have the heavy duty of keeping up a 20-gallon tank. If you want to make sure everything is running smoothly, you need to do daily checks on the water’s temperature, filtration rate, alkalinity, and marine life’s health.

Use an automated feeder to prevent your pets from going hungry while you’re gone, but have a buddy swing by to check on the water level in the tank every so often.

Your fish won’t suffer if you show a friend or relative how to check the aquarium for problems and take care of the fish in your absence.

A battery-powered feeder will continue to work even if the power goes out, but your fish will likely perish without access to a filter and heater. Until electricity is restored, a home sitter can relocate the tank.

The convenience of feeders is tempered by the fact that not all models are compatible with the various tank sizes. Even though it’s a great aquarium overall, the AquaSphere 360 doesn’t allow for a clip-on feeder to be attached to it. A straight edge, as opposed to a rounded one, is necessary for the operation of clip-on feeders.


A great 20-gallon tank is available, and BestForPets (bestforpets.org) wants to help you discover the best 20-gallon aquariums with our reviews and buying advice.

We have reviewed several high-end aquariums, but the Aqueon LED Aquarium Starter Kit emerges as a clear winner. The compact design and high-quality tools and materials included in the package made us win.

Marina LED Aquarium Kit appears at the end moment. The Marina may lack the Aqueon’s fireplace, but makes up for it with a wealth of useful features and designs that make filter replacement a breeze.


Best All-Around: Aqueon LED Aquarium Starter Kit

  • Length x Width x Height: 24.2 x 12.5 x 19.5
  • Measures in at a hefty 33.2% of a human’s body weight
  • Kit for introducing fish to fresh water

The Aqueon LED Aquarium Starter Kit is a good option if you’re searching for a complete set for a new aquarium owner. A competition was held to choose the greatest 20-gallon aquarium, and this one won.

The Aqueon takes up far less horizontal space than traditional tanks because of its vertical shape and thicker walls, which eliminate the need for a lengthy stand or table. The elegant design has a slim LED hood and a Quietflow LED power filter.

The Aqueon kit’s wide variety of useful extras wowed us. It comes with a fish net, quality fish food, a thermometer, a water conditioner, and a submersible heater. The aquarium’s fixed heater is its one drawback.

The heater will raise the water temperature too high to sustain cold-water fish.


  • The space-saving high walls
  • Light-emitting diode cap with a low profile
  • Including a heating element, temperature gauge, and water softener


  • A heater is not appropriate for all species of fish.


The Most Economical Marina LED Aquarium Kit

  • Dimensions: 24″ x 12″ x 16.5″
  • Weight: 35 pounds
  • Kit for introducing fish to fresh water

When comparing 20-gallon aquarium kits, the Marina LED Aquarium Kit came out on top. Although some fish are affordable, you may spend a lot on a tank and other materials when you purchase other kinds.

Betta, goldfish, and cichlids would all do well in the Marina aquarium. A day’s worth of light is replicated by the long-lasting LED lighting, and filters can be changed in under a minute thanks to the clip-on design.

The kit also contains a Nutrafin Aqua Plus water conditioner, fish food, and a biological supplement. The tank is appropriate for novices who love cold-water fish, but you’ll need to buy a heater if you’re maintaining warm-water species.


  • LED lights that endure for a very long time
  • Clip-on filter is simple to modify
  • Includes meal, a biological supplement, and fish food


  • Does not include a heater


The Best Fish Tank on the Market: The Penn-Plax AquaSphere

  • This item is 24 inches long, 24 inches wide, and 18.5 inches high.
  • Weighing in at 16.55 lbs.
  • Filtered round fishbowl

The Penn-Plax AquaSphere 360° Fish Aquarium had to make the list despite the fact that it does not come in a 20-gallon size. It comes in 10, 14, and 24 gallon containers.

On the webpage, it appears to be a small fishbowl, but in reality, it is a large aquarium that will wow your visitors when you display your marine life. The bowl has two skimmers, a low-voltage LED light, and a top-mounted filtration system.

Simply touching the LED panel will switch the light to either red, blue, or green. The 360 may be used in either saltwater or freshwater environments, and its performance has been praised by its owners.

Customers complained that the Penn-Plax filter was excessively noisy, therefore they recommended looking into alternatives.


  • Round and aesthetically pleasing
  • There are three different levels of brightness
  • Needing a more diminutive foundation than conventional rectangular tanks


  • Filter with poor design


Aquarium with Tetra ColorFusion

  • Overall dimensions are 27.88″ in length, 16.13″ in width, and 20.38″ in height.
  • Mass: 34.6 ounces
  • Kit for introducing fish to fresh water

Although the Tetra ColorFusion Aquarium 20 Gallon Fish Tank KitT is more expensive than many of its rivals, it is the best option for novices.

The ColorFusion may not be the right choice if you’re in the market for a standard tank. You may proudly display your fish and plants in one of the most aesthetically pleasing tanks we looked at.

The LED screen may be configured to flash through several colors or to maintain a steady glow.

The set has everything you need to start your own aquarium, including a UL heater, Tetra Whisper 20 filter, color-changing LED, two Wonderland plant multipacks, and a white anemone in bloom.

While the ColorFusion often receives positive feedback from buyers, some have noted that the Whisper 20 filter is noticeably noisier than those on competing 20-gallon tanks.


  • LEDs that change color show a wide range of hues
  • Such as anemones and Tetra plants
  • Reliability and longevity are guaranteed with a glass tank.


  • I can’t hear anything through the filter.


Set for a 20-Gallon Tetra Aquarium

  • Overall dimensions are 27.88″ in length, 16.13″ in width, and 20.38″ in height.
  • The total amount of weight is 34.15 pounds.
  • Kit for introducing fish to fresh water

The Tetra Aquarium 20 Gallon Fish Tank Kit is a great option if you aren’t interested in the sophisticated color-changing show that the Tetra ColorFusion provides. It has the identical proportions as the ColorFusion, but it’s more cheap.

This set includes a 20-gallon glass aquarium, a boxwood plant mat, four fake plants, and a UL heater. Gravel, fish, and food for the fish are the only other need.

Customers who have remarked on the Tetra tank have been overwhelmingly newcomers who are pleased with the long-lasting tank. Some fish parents, however, have complained that the hood sealant is ineffective.


  • Reinforced, scratch-proof glass
  • Includes four fake plants
  • Put together with minimal effort


  • This LED cap won’t last long.

Author Image

Dr. Barry Buttler

Dr. Barry Buttler, DVM, MS, DACVIM, is an experienced veterinarian who specializes in the care of small animals, specifically dogs. Dr. Barry K. Buttler is a member of the American Veterinary Medical Association and holds multiple certifications in small animal emergency medicine and geriatric pet health.

Veterinarian (DVM) Dr. Barry Buttler


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