Best 20 Gallon Aquarium – Review & Guide

Are you thinking about getting a fish or reptile? This first thing you need to look for is an aquarium. The aquarium is their home, and the base for everything else your aquatic animals need.

To keep happy and healthy fish and reptiles, you need a filter, heater, decorations, and more. The size and shape of each of these things will be determined by the aquarium you use.

Your aquarium will come as a kit or on its own. If you are new at this, the kit may be a great idea. If you want more control, look at stand-alone tanks.

Once you decide if you want a kit, this guide will help you pick other features. Do you want glass or acrylic? Should you get a floating base or not?

20 Gallon Aquarium Reviews

Aqueon LED Aquarium Kit 20H Black

The Aqueon LED kit comes with a heater and filter. It has a hood with a light, and is made of glass to make for a clear view. It weighs about 100 pounds when full.

This aquarium comes with a water heater. It is preset to the right temperature for most tropical fish, and is essential to the health of many aquatic animals.

The hood has LED lights to showcase the aquarium inhabitants. This hood is low profile, so it does not take attention away from the animals beyond the clear glass.

The aquarium comes with a filter. The filter keeps water clean and livable. This filter has a red LED light that tells when to change the filter, and makes it easier to maintain.

  • It comes with a setup guide.
  • The glass makes for a clear view.
  • It is a complete kit, with food, a filter, a heater, and everything else needed for setup.


  • It is heavy when full, at about 100 pounds, and must be on a sturdy surface.
  • The heater and filter are too small and may need replacement.

Aq Ascent LED Kit

The Aq Ascent LED kit is a full aquarium kit that comes with a filter and other features. It has a clear view, due to a unique shape and LED lighting.

This aquarium has an angled top to make the water line less visible. This combines with the LED lighting to make a large window for you to view your aquatic animals through.

The modern design, angled top, and polished edges give a clean appearance. This sleek and open design make it a subtle addition to a room.

The floating base means that there is less strain on the bottom of the tank. The aquarium bottom is less likely to crack, and it can handle sitting on uneven surfaces better than some aquariums.

  • The floating base makes the bottom less likely to crack.
  • The angled top increases viewing space.
  • Concealed LED lighting gives maximum visibility.
  • It comes with the materials you need to set it up.


  • The black background can make it hard to see the fish or reptiles inside.
  • The lighting may not be enough.
  • The filter may not be strong enough for the size tank.

GloFish Aquarium Kit Fish Tank

This aquarium comes with everything you could need to start your first aquarium. It has a heater, filter, LED lights, and hood. It also comes with plants, fish food, and a set-up guide.

This aquarium comes with an anemone and blue LED lights. Combined with glowing fish, it creates a neat effect that other tanks will not have.

It comes with a heater that keeps the tank at the right temperature. Many fish and other aquatic animals are sensitive to temperature changes and cold. This heater is essential to keep them alive.

The aquarium kit comes with plants and a filter. These are important for clean water and oxygen to keep the inhabitants healthy. Most tanks do not say they include plants.

  • It is a complete kit with plants, an anemone, fish food, and anything else you may need.
  • The blue LED creates a cool look.
  • The set-up guide and included items make it great for beginners.


  • You may need to replace the filter with a better one, since the one it comes with is not strong enough.
  • The glass or plexiglass may be thin and crack easily.

Marina LED Aquarium Kit

Marina designed this kit for beginners. It has a guide to help you set up the environment. It also has all the materials you will need to make your aquatic creatures thrive.

It is made of glass. The glass is heavier than acrylic, and runs the risk of breaking. Glass does not scratch as easily, and your view inside the aquarium should be clearer.

The aquarium has a lighting module in the canopy. The LED light is designed to mimic natural daylight and create a healthier lighting for the inhabitants.

This kit is fully stocked, including water conditioner and a biological supplement. These make tap water safe for fish and help create a healthy environment in the aquarium.

  • It comes with an aquarium guide to help new fish owners.
  • The biological supplement helps make a healthy aquatic environment.
  • The glass will not scratch as easily as some materials would.


  • The glass tank is heavy, so you must put it on a sturdy surface.
  • The filter is not strong enough for the tank and you may need to replace it.

Marineland (Aquaria) AMLPFK20B Biowheel Aquarium Kit

This aquarium is energy-efficient and easy to use. It has a convenient hinged hood for easy access during maintenance, as well as several types of filtration.

The aquarium comes with LED lights that simulate the shimmering effects of natural light underwater. It also comes with night light LEDs, so you can look inside during the day or night.

The hood is hinged to make the tank accessible for feeding and cleaning, and has places to put filters and heaters. The hinged design also keeps debris out when you are not feeding or cleaning.

The aquarium comes with several types of filtration. The filters are easy to maintain and keep clean. One has cartridges to change out and the other does not need to be changed often.

  • Glass is less likely to scratch than other materials.
  • The hood has convenient hinges and places to put accessories.
  • The lights mimic natural light during the day and at night.


    • You cannot replace individual LEDs, and must order a whole new bar to replace them.
  • Glass is fragile and can break during shipping.
  • Glass is heavy.

SeaClear Acrylic Aquarium Combo Set

This acrylic aquarium is lighter and clearer than most. It is less likely to break than glass. The clearer sides and bright light make it great for viewing.

This Aquarium comes with a reflector and 15-inch light fixture. This ensures that light is directed into the aquarium for maximum effect. This is particularly important if you want a lot of plants.

The aquarium is acrylic, which is lighter than glass. It is also less likely to break, but can scratch easier. The acrylic allows it to come in both hexagonal and rectangular shapes.

The aquarium has virtually invisible seams, making the view clearer. Unless something scratches it, the acrylic material also makes the view clearer, adding to the decorative value of the tank.

  • It is lighter than a glass tank.
  • It comes with a reflector to angle light properly.
  • It comes in both rectangular and hexagonal shapes.
  • It is less likely to break than glass.


  • The acrylic material scratches easier than the more common glass aquariums.
  • Non-LED lightbulbs may not last as long as the more common LEDs, and may use more energy.

Tetra Complete Aquarium Kit

The Tetra 20-Gallon Complete Aquarium Kit is made of durable glass for a clear view. It has lighting and materials that mimic a natural environment for you and your animals to enjoy.

This aquarium comes with fake plants and an LED hood. The LED lighting simulates natural daylight and helps the plants grow. The two combine to give a natural feel for you and your fish.

Tetra makes these aquariums with scratch-resistant glass. The glass will be heavier and more fragile than other mediums, but it keeps the aquarium in good shape and keeps your view of the inside clear.

This aquarium comes as a kit with a heater and filter. These work together to keep your tank clean and warm enough to support your aquatic animals.

  • The plants and lighting mimic a natural environment and reduce fish stress.
  • The scratch-resistant glass leaves you with a clear view inside the aquarium.
  • It comes with a filter and heater.


  • It is made of glass, which is heavier than acrylic, and so harder to handle.
  • The glass is more likely to break than more durable mediums.

Tetra Aquarium Reptile Glass Kit

Tetra designed this Tetra Aquarium Reptile Glass Kit with two domes lamps for aquatic turtles. The basking options and supplied food make it best for turtles, newts, frogs, or other reptiles.

The accessories in this kit are geared towards aquatic turtles rather than fish. It includes a basking platform for reptiles, as well as dome lamps to give them warmth to bask under.

This kit has a decorative filter that forms a waterfall while keeping the tank clean. This leads to a nice look as the clear water filters down in a waterfall.

The tank has a screen top to keep debris out of the tank. The top lets light from the dome lights through, but keeps outside dirt and animals from harming the inhabitants.

  • The screen at the top makes the tank a cleaner and safer place to store aquatic animals.
  • It comes with water care samples and food for your animals.
  • It comes with a decorative filter.


  • It comes with specific decorations, so you cannot pick and choose which ones you want.
  • The filter is not of great quality, and you may need to replace it.

SeaClear Acrylic Aquarium Junior Executive Kit

This tank is great for reptiles or either saltwater or freshwater fish. It comes with decorations to give a natural feel and look to the environment.

It is acrylic. This means it is lighter and less likely to break than glass tanks. It also means it is more likely to get scratches that can block your view of the inside.

The aquarium kit comes with a fluorescent light fixture and heater to keep the water warm and well-lit. This, along with the included filter, creates a healthy environment for the inhabitants.

It comes with a lava rock and fake plants for decoration. These create an attractive and natural look for both you and your aquatic animals to enjoy.

  • The clear acrylic gives a good view of the inside.
  • It is lighter than a glass tank.
  • It can be used for freshwater fish, saltwater fish, or reptiles.


  • It is acrylic, and will scratch more easily than a glass tank.
  • The lights are fluorescent, and will not last as long as LED should.

Perfecto All Glass Aquarium Tank44

The Perfecto All Glass Aquarium Tank44 is perfect for any number of animals. It can be used for saltwater and freshwater fish, aquatic animals, or as a dry tank for a gecko or other animal.

This aquarium is made of glass. This means that it will be more resistant to scratches than an acrylic tank. It also increases the weight and makes it more likely to break.

It is corrosion-proof. This means it can be used for saltwater fish and aquatic life. It can also be used by reptiles or freshwater fish.

The aquarium is on the tall side, at 16 inches tall, 24 inches long, and 12 inches wide. It works well as a dry tank or for aquatic animals.

  • It is corrosion proof, so you can use it for saltwater fish.
  • The glass is less likely to scratch than acrylic.
  • It is not part of a kit, so you can choose your own accessories.


  • It does not come with a screen top to keep debris out of the tank.
  • It does not come with any extra parts, such as filters and heaters.

Types of 20-Gallon Aquariums

  • Stand-Alone. A stand-alone aquarium does not come with any accessories, such as a filter and heater. This means that you can choose which heater, filter, decorations, and other items you want. To do this, you will need to research or have experience. It also means you can pick the best materials for the type of fish you have.
  • An aquarium kit is great for a beginner. It comes with most of what you will need to get fish or reptiles started. That also means you cannot pick which filter, heater, or decorations you get. This can lead to lesser quality setups, as filters that come with these kits are often underpowered.
  • Aquariums can be glass or acrylic. Acrylic aquariums are lighter and harder to break than glass ones. This makes them great for shipping and easier setup. They scratch easier than glass, which can lead to a less clear view into the tank.
  • Glass aquariums are harder to scratch, leading to a clear view of any fish or aquatic life in your tank. They are heavier, though, and can break easier. This makes shipping and installing more difficult.
  • Floating Base. Some tanks have floating bases. A floating base means that the pressure from inside the tank is directed to the sides rather than the bottom. This makes it less likely to leak, and means it can sit on a less even surface than other aquariums.

How to Select a 20-Gallon Aquarium

  • Are you experienced or a beginner? While experienced aquatic animal owners may know what to get, a new pet owner will need some guidance. There are kits available if you don’t know what accessories to get.
  • What kind of environment do I want for my aquarium? This tank could be a species or breeding tank with all one species in it. This means you can customize the tank for species, rather than getting a generic kit. For a community tank, a kit will give you an idea of the types of fish that are good with the provided materials.
  • How much space do you have? This will tell you whether you need a tall or short tank. 20-gallon aquariums will all be about the same size, but they may be different shapes, so check the dimensions in the product description.
  • Do you want fish or reptiles? Reptiles will need light for sunning. Many aquariums have the light source built-in, so you may need to pick one that has the right lighting for your animal.
  • What species do you want? Each species has specific needs. Some prefer tall plants, and some prefer short plants, which will tell you whether you want a taller or shorter tank. They may prefer more or less light.
  • Do you need saltwater or freshwater? Some tanks can handle saltwater, and some cannot. If the aquarium comes in a kit, you will need to find out if the kit is designed for saltwater.

Frequently Asked Questions About 20-Gallon Aquariums

Should I buy a kit or a stand-alone tank? A kit is great for beginners, but may have lesser quality materials, and cannot be customized. If you are experienced, consider buying each item separately.

What filter should I put in my aquarium? Filters should have a GPH (gallon per hour) that is at least 4x the gallons in the tank. For your 20-gallon tank, get one with 80-120 GPH.

What heater should I put in my aquarium? Know the room temperature where the aquarium will be. This will determine how strong your heater must be. A temperature dial and shutoff sensor are good features to look for.

Can I put more than one type of fish in the same aquarium? Each aquarium will be better for certain types of fish. Look at which fish go well together. If you get a kit, make sure the accessories fit the fish types. Otherwise, choose an aquarium and buy the accessories separately.

Do I need a special aquarium for a reptile? Look for aquariums that mention reptiles or basking areas. They should have lights for the reptiles to sun themselves in. Other tanks with built-in lights may not give off the right light for reptiles.

Should I use live plants? Live plants are a valuable part of your aquarium’s ecosystem. They help oxygenate the water and keep animals healthy. That said, you don’t have to have them.

How to Maintain Your 20-Gallon Aquarium

The most important thing you will do to maintain an aquarium is keep it clean. This is done with a good-quality filter most of the time. Make sure to clean the filter regularly. Do not clean the filter at the same time as the water.

You will have to clean the tank manually sometimes. When you clean, do not change all the water out. If you change all the water out for tap water, you will kill much of the bacteria keeping your aquatic animals healthy. Instead, replace about 10-25% of the water every 2-8 weeks, depending on how many fish of what sizes you have. Make sure the water is not chlorinated.

Vacuum the gravel. The bottom layer of your tank can get dirty. Every so often, you will need to use a gravel vacuum to clean the gravel and water at the bottom of the tank.

Make sure to have a bucket on hand while cleaning the tank. You will need this to remove dirty water and replace it with new water. Remember that fish are sensitive to what goes in their water, and do not reuse household mop buckets. Residue from cleaners can poison the reptiles or fish.

Keep the aquarium covered if you can. An aquarium with a screen or lid is great, because it keeps debris out. Covering your aquarium is a form of preventative maintenance, and will keep the water clean for longer.

Last, test the pH regularly. Much of what biological filters help with is high ammonia content. This can cause the pH to be low, so pH is a good indicator of how clean the water is. This is more likely to be a problem if the water in your area is acidic. If you have hard water, it is less likely to be a problem.

How to Set Up an Aquarium


These tanks all have their pros and cons. Glass will not get scratched, but acrylic is light and hard to break. Kits are good for beginners, but do not have the flexibility you may want.

Each type of fish or reptile has its own needs, and your aquarium is a reflection of that. Find one with enough light and space, and maybe some good accessories.

Did you find a product you liked or disliked? Do you already own one of these? Tell us all about it in the comments below.

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