10 Best 20-Gallon Aquariums in 2024 – Reviews & Top Picks

Fishkeeping is a rewarding hobby, but it can seem challenging in the beginning when you are unsure which products you’ll need. Selecting an aquarium is the first step, and a 20-gallon aquarium is ideal for beginner aquarists. Some companies include starter kits with everything you need except fish, and others sell bare tanks without lights, filters, or heaters.

We’ve examined the best tanks on the market and picked ten of our favorite brands. Our reviews and buyer’s guide can help you choose a reliable aquarium for your home.

A Quick Comparison of Our Winners (2024)

The 10 Best 20-Gallon Aquariums

If you’re looking for a beginner kit with everything you’ll need, you can try the Aqueon LED Aquarium Starter Kit. It scored the prize for the best overall 20-gallon aquarium. Unlike other tanks that require a long stand or table for support, the Aqueon has a vertical design with higher walls to take up less horizontal space. It has a sleek style and comes with a low-profile LED hood and Quietflow LED power filter.

We were impressed by the number of accessories the Aqueon includes in the kit. It has a thermometer and setup guide, submersible heater, water conditioner, premium fish food, and a fish net. The only downside to the aquarium is the preset heater. If you’re planning on keeping cold-water fish, the heater will make the water temperature too warm.

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The Marina LED Aquarium Kit beat out the competition for the best 20-gallon aquarium for the money. Although some fish are inexpensive, you can spend a bundle on a tank and other supplies when you purchase other brands. The Marina tank is perfect for keeping betta, goldfish, or cichlid. The clip-on filter design allows you to replace filters in less than a minute, and the long-lasting LED lighting provides daylight-like illumination for your fish and plants.

The kit also includes a Nutrafin Aqua Plus water conditioner, fish food, and a biological supplement. The tank is suitable for beginners who prefer cold-water fish, but you’ll need to buy a heater if you’re keeping warm-water species.

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Although the Penn-Plax AquaSphere 360° Fish Aquarium is not available in a 20-gallon tank, we had to include it on our list because of its unique design. It’s available in 10, 14, and 24 gallons. It looks like an ordinary fishbowl on the website, but it’s a massive tank that will impress your guests when you show off your marine creatures. The bowl comes with a top filtration system, a low-voltage LED light, and two skimmers.

You can change the lighting color to red, blue, or green by merely touching the LED panel. The 360 is suitable for saltwater and freshwater systems, and most aquarists were happy with the tank’s performance. However, some customers suggested buying another filter because the Penn-Plax filter was too loud for bedrooms.

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4. Tetra ColorFusion Aquarium

The Tetra ColorFusion Aquarium 20 Gallon Fish Tank KitT is perfect for beginners, but it costs a bit more than many of its competitors. If you’re looking for an ordinary tank, the ColorFusion may not be for you. It’s one of the most attractive tanks we reviewed, and it shows off your fish and plants with style. The LED display can be set to cycle through multiple colors or stay lit with one hue.

The kit includes a UL heater, Tetra Whisper 20 filter, color-changing LED, two Wonderland plant multipacks, and one blooming white anemone. Most customers were satisfied with the ColorFusion, but some mentioned that the Whisper 20 filter is much louder than filters on other 20-gallon tanks.

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5. Tetra Aquarium 20 Gallon Fish Tank Kit

Tetra’s ColorFusion is an excellent product, but if you’re not looking for a fancy color-changing display, you can try the Tetra Aquarium 20 Gallon Fish Tank Kit. It has the exact dimensions as the ColorFusion, but it’s more affordable. The kit comes with a UL heater, Tetra Whisper 20 filter, four artificial plants, a boxwood plant mat, and a 20-gallon glass tank. All you need to add is gravel, fish, and fish food. Most of the customers who commented on the Tetra tank were beginners, and they were happy with the durable tank. However, some fish parents mentioned that the sealant on the hood does not keep the unit secure.

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6. GloFish 20 Gallon Aquarium Kit

The GloFish 20-Gallon Aquarium kit provides a colorful fluorescent display by illuminating the tank with bright blue LED light. It’s designed to highlight the colors of your glofish and create a stunning focal point for your home. Glofish are genetically modified fish with brilliant colors, but their appearance is unimpressive when they’re in another dimly-lit tank.

The aquarium is made of scratch-resistant glass, and it comes with a GloFish light stick, yellow anemone, Tetra Whisper 20 filter, three GloFish plants, and a UL heater. Although most fish parents were pleased with the aquarium, some were disappointed the lid was constructed of flimsy plastic.

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7. SeaClear Hexagon Acrylic Aquarium

Most aquariums have plastic borders that hide the seams of the glass, but the SeaClear 20-Gallon Hexagon Acrylic Aquarium has invisible seams that are designed to last. The acrylic tank is lighter than any brand on our list, and the hexagonal design requires less space than rectangular aquariums. The kit includes an AquaClear 30-gallon filter, artificial plants, natural lava rock, fish net, and a thermometer.

The seamless design gives you an unobstructed view of the tank, and most customers were satisfied with the aquarium’s stylish appearance. However, several aquarists were disappointed with the light fixture because it stopped working in a short time. Also, it’s one of the few aquariums that does not include a bulb for the light.

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8. SeaClear Acrylic Aquarium Combo Set

Glass tanks can get heavy after adding gravel, water, and plants, and you need a durable base to support the weight. With the SeaClear 20 gal Acrylic Aquarium Combo Set, you do not have to worry about a stand collapsing under the tank’s weight. The acrylic construction has invisible seams, so your view is not obstructed by black plastic trim.

Unlike many of the 20-gallon tanks on the market, the SeaClear is suitable for freshwater or saltwater setups. Although the tank is supposed to be much stronger than glass, some customers noticed that the top of the aquarium became warped over time. Compared to other starter kits, the SeaClear does not include many accessories.

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9. Aqueon Aquarium

We reviewed several starter kits that come with accessories, but some amateur aquarists prefer buying their equipment separately instead of in a bundle. The Aqueon Aquarium 20 Gallon Long is a rectangular 20-gallon tank that’s reasonably priced, but you’ll need a hood and filter, lighting, gravel, and anything else you want to include inside the tank.

Shipping problems are not uncommon, but the Aqueon had so many complaints we could not place it higher on the list. Although damage can occur when packages are mishandled, the Aqueon’s issues seem to be related to a design flaw rather than a heavy-handed delivery driver.

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Fishkeeping is not a low-cost hobby, but you can use the Tetra Shippable Clear Aquarium if you’re looking to save money. The Tetra was the most affordable product on our list, and you’re unlikely to find another 20-gallon tank with a better price. Because it’s relatively new, we could not find many comments about the tank’s quality.

However, we found more negative reviews than positive ones, and one customer mentioned the plastic trim cracked after filling it with water. If the tank had been constructed with more durable materials, we would have considered it for our best value pick. This model may be better for turtles or other small reptiles than fish.

Buyer’s Guide: Buying the Best 20-Gallon Aquarium

If our reviews have not helped you pick your favorite aquarium, you can look at these tips for selecting the right tank for your home.

Starter Kit or Bare Tank?

Starter kits are designed for beginners, and they save you the trouble of shopping for equipment and supplies. In some respects, you can save money when you order a kit. If you can buy a tank, hood and filter, heater, and LED light for under $200, it sounds like an affordable package.

However, the price on some kits may indicate that you’re not getting the highest quality accessories. Our top picks had fewer problems than the other kits on our list, but you should be prepared to replace a component when buying a complete package.

For instance, the Tetra ColorFusion aquarium (#4) is a highly rated aquarium kit, but some customers could not tolerate the filter’s sound. It did not have any structural problems, but a noisy filter can disrupt your sleep if you keep an aquarium in a bedroom. Another factor to consider when buying a kit is that you may not need some of the accessories to care for your fish. If your fish do not need heated water, there’s no reason to purchase a package with a heater.

You’ll spend more when you start with a tank and buy the components separately, but you have the freedom to pick premium aquarium filters, lights, decorations, and supplies. You may spend more initially when you purchase top-of-the-line parts, but you’ll spend less on replacing faulty equipment.

Choosing Fish for 20-Gallon Tanks

A 20-gallon tank is perfect for beginners, but you have to be cautious when selecting fish. Before choosing a fish, research it thoroughly to learn how large it will grow. Goldfish are often kept in round bowls and small tanks because they’re hardier than other species, but that does not mean that they’ll live long lives in inadequate environments.

A 20-gallon tank is suitable for a single goldfish when it’s young, but it can grow over 12 inches long, depending on the species. A 75-gallon tank or larger is more appropriate for adult goldfish.

Decorations

Plants, rocks, and other decorations add color and style to your aquarium, but it’s easy to overload the tank with unnecessary items. Some fish swim around constantly, but others prefer to hide behind plants and hover. If you have quick swimmers instead of hiders, you should minimize the number of decorations to give them more space.

If you’re new to fish keeping, you may have more luck starting with artificial plants instead of living ones. They’re not as attractive as real plants, but they will not die if the water chemistry is not ideal. After you’ve had an aquarium for a couple of months, you can switch to live plants.

Aquarium Care for Vacationers

Maintaining a 20-gallon tank is a significant responsibility if you want your fish to thrive and live for several years. You have to check the water temperature, filtration efficiency, water alkalinity, and condition of the marine life every day to ensure the system is functioning correctly.

When you leave town, you can use an automatic feeder to keep your pets from starving, but you’ll need a friend to stop by to check the tank’s condition. If you teach a family member or friend how to inspect the aquarium and care for the fish, your fish will not suffer if something goes wrong. A power outage will not affect a battery-operated feeder, but your fish can die when the filter and heater are off. A house sitter can move the tank to another location until the power is restored.

Although feeders are convenient, some units will not work on all tanks. For instance, the AquaSphere 360 is an excellent aquarium, but it cannot be fitted with a feeder using a clip-on attachment. Clip-on feeders require a straight edge rather than a rounded one to function.

Conclusion

We hope our reviews and guide will help you on your quest to find the perfect 20-gallon tank. We researched several high-quality aquariums, but the Aqueon LED Aquarium Starter Kit was our top choice. We liked the space-saving design and the valuable components and supplies included in the kit. Our second choice was the Marina LED Aquarium Kit. Although it does not have a heater like the Aqueon, the Marina is packed with practical equipment, and the clip-on design enables quick filter changes.