Best 20 Gallon Fish Tank

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Are you looking for the best 20 gallon fish tank? Then you are in the right place!

A 20 gallon fish tank or aquarium is perfect for new fish keepers; it’s large enough to have a nice selection of fish, yet small enough to maintain and keep stable.

A tank of this size allows you to keep a wide variety of different fish, live plants and invertebrates such as snails or shrimps.

If you are in a hurry then this tank is my favorite tank because it is of high quality, is made from a well known and established brand and has the most important equipment included in the price.

There is a bewildering array of tanks to choose from. There are different shapes and styles and some are made from glass while others are made of acrylic.

So, it can be hard to tell if you are choosing the right one.

I have put in the research and used the knowledge gained over the years to make your decision easier.

I have read many reviews; manuals and manufacturers notes to make sure you’re getting the best 20 gallon fish tank to suit your requirements and needs.

Here are my top choices:

1) Marina LED Aquarium Kit 20 Gallon – Best Starter Kit

The kit includes:

  1. Marina Slim S20 clip-on filter with quick-change filter cartridges
  2. Natural daylight-effect LED lighting
  3. An aquarium care guide
  4. Nutrafin Max fish food
  5. Nutrafin Aqua Plus water conditioner
  6. Nutrafin Cycle biological supplement
  7. A fish net

The Marina LED Aquarium Kit is a great tank for beginners . It is made of glass and measures 24 inches L x 12.5 inches W x 16.5 inches H.

This is a trusted and well known brand with fish keepers world wide.

The hang-on-back filter is a 3 stage filter that is very efficient for this size tank. You can use different filter media in some of the compartments.

Change one compartment each week to keep the beneficial bacteria alive and well.

The LED light that is included has a natural daylight effect and it is incorporated into the tank canopy.


  1. Everything needed is included except for a heater   
  2. Well known and established brand
  3. The tank is made of glass
  4. The HOB filter has 4 chambers


  1. The filter pump is a little noisy
  2. The LED light is only a daylight light
  3. The cover is flimsy
  4. Not suitable to be used as a saltwater tank

This is a great tank kit when you consider everything that has been included. It makes it easier for a beginner to buy as most of the equipment is included in the price.

2) Glofish Aquarium Kit Fish Tank with LED – Perfect for Kids

If you want a tank that the kids and you can enjoy, then this tank could be a good fit. It might not suit everyone but it is a great tank nevertheless.

This kit includes:

  1. Tetra Whisper 20 Filter
  2. GloFish 13″ LED light stick
  3. 1 GloFish yellow anemone & 2 plant multipacks
  4. Tetra mini UL heater
  5.  Fish food and water conditioner
  6. Setup Guide

With the GloFish Aquarium Kit Fish Tank you can create a fun and colorful aquarium.

This unique glass aquarium will be an interesting focus point with it’s fluorescent lighting and plants.

It an also act as a night light for your child’s bedroom.


  1. This kit includes a heater
  2. It is very easy to set up
  3. The Tetra Whisper filter is quiet and has a good flow


  1. Lid is a little flimsy and sometimes does not close properly
  2. The filter intake tube is a little short

Add on’s

GloFish Aquarium Decorations and gravel

Glofish has created many fish tank decorations and plants that you can add to the tank to make it unique and colorful.

3) Seaclear Acrylic Aquarium Combo Set – Best Acrylic Tank

Acrylic is much stronger than glass and it also allows for the tank to have a seamless finish. Acrylic is clearer than glass and it is more impact resistant.

This kit includes:

1. The tank

2. A reflector

3. An electrical 15″ light fixture

This is a stunning and beautiful aquarium. So, if you are looking for a more elegant and refined fish tank the SeaClear Acrylic Aquarium is a good choice.


  1. Beautiful looking tank 
  2. Acrylic is clearer than glass
  3. It weighs half the amount that a glass tank would
  4. Less prone to cracking or chipping
  5. Can be used for fresh and salt water


  1. Can be easily scratched when cleaning
  2. There is no heater or filter included

4) 20 Gallon Fish Tank only

You might already have all the equipment that you need and just need the tank.

Make sure though that you have the correct hood needed for the tank as these can vary slightly according to the brand bought.

What You Need to Know When Buying a 20 Gallon Aquarium

The first decision you will need to make when choosing your 20 gallon fish tank will be if you would like to buy a kit or just the tank?

If you are planning on buying a kit then look at the amount of accessories that come with your purchase. Is all of the important equipment included or will there be extra stuff that you would need to buy?

Besides the tank itself, the most important piece of equipment will be the filter. You want a 20 gallon kit that features a great filtration process so that your fish will have a clean environment.

This will also help to keep the water clean.

The design of the tank is also important. Make sure your new aquarium will look great where you have planned to set it up.

Design and functionality go hand in hand.

The available lighting options are the next important consideration. Most aquarium kits come standard with LED lights. This is because LED lights are great for energy conservation and performance.

Lights are important so that firstly, you can see your fish but more importantly they are needed to ensure better plant growth.

20 gallon fish tank

Setting up your 20 Gallon Aquarium

If you decided on purchasing the kit then setting up the tank should be easy as normally all the equipment included in the kit will be correct for that size aquarium.

Every kit should come with the manufacturer’s instructions and it is important that you read through them so you understand how to correctly set up the tank.

There should be diagrams and a very detailed description of the whole process.

You can also check out videos on YouTube if you need more of a visual look at how to setup the tank.

How much does a 20 gallon fish tank weigh?

A filled tank can weigh even more if you have used rocks as decorations. The filled weight shown in the table is just when water has been added.

Tank SizeLxWxHEmpty TankFilled Tank
20 gallon High24″ x 12″ x 16″25 lbs225 lbs
20 gallon Long30″ x 12″ x 12″25 lbs225 lbs

Stocking Ideas for your 20 Gallon Tank 

It is important to match fish together so that you can create the ideal environment for you and for them.

Below are some options of what setups you can create with your 20 gallon fish tank.

A Peaceful Community Tank

This is my favorite option because you can combine a few different types of fish so that you have variety.

If you choose small peaceful fish then you can create a beautiful community tank.

I would then have one bigger fish like a Dwarf Gourami or Anglefish as a centerpiece fish.

At the moment I have 6 Cardinal Tetras, 3 Cory Catfish and one male Dwarf Gourami in my 20 gallon peaceful tank.

You could consider a ‘Tetra’ tank where you have 3 Black Tetras, 5 Neon or Cardinal Tetras and 5 Glowlight Tetras. Tetras are peaceful fish.

You can also add some snails if you want something different. Just be careful as some species of snails can quickly become a nuisance.

A Breeding Tank

If you are like me and have Guppies and Platies then at some stage you will need a breeding tank to cope with all the offspring. Livebearers are prolific breeders and you will end with with babies in the tank.

When they are a little older then your tank will be too small to house everyone. A 20 gallon tank is perfect for raising young fish.

A Species Only Tank

Neon tetras

You might only be interested in one species of fish. Tanks holding just one type of fish can be very striking.

A school of Cardinal Tetras comes to mind. There flashing blue and red is very eye catching and when they are in a group, they really look spectacular.

You can also house a Betta Fish sorority (female bettas).

I have also created a species only tank when I was breeding Apistogramma as these are very aggressive fish that are best kept alone, especially when they are in breeding mode.

Go here to discover how many fish you can fit into your 20 gallon fish tank.


Hopefully I have helped you make the right decision on which 20 gallon fish tank to buy. I have chosen the tanks that I think are the best available.

It has become much easier to set up a tank, especially if you buy one of the kits as most of the equipment that is needed is already included.

Photo of author


Irma Bense is the founder of She has over 42 years of experience in keeping fish.She has kept both freshwater and saltwater fish through the years.She has extensive knowledge in breeding numerous species of fish from Show Guppies, Cory Catfish, German Blue Rams to Apistogrammas.You can learn more about Irma on the 'About' page.