What Pets Can Live In A 20 Gallon Tank?

What Pets Can Live In A 20 Gallon Tank

Do you know that you can actually start your fish keeping journey with just a 20 gallon tank?

If you are so passionate about keeping aquarium animals, but you don’t have the huge finance to buy huge tanks like the 120 gallon or 200 gallon etc, then you can actually buy a 20 gallon and start from there, depending on your finance.

The truth is, a 20 gallon tank is too small for a huge size aquarium and could only contain few or little number of water animals as the case may be.

A 20 gallon tank is not that expensive, as you can get them even online on Amazon or Petco.

In this article, we will be Talking about the kind of aquatic pets that you could keep in such a small tank and the possible numbers such a tank could contain.

Related: What pets could live in a 1 gallon tank?

Such pet. includes:

Crabs: can live In 20 Gallon Tank

If you have this small tank or you’re planning to have it, then crabs should be an option for you, that’s if you are a fan of them.

There are different types of crabs such as hermit crab, fiddler crab etc, find the one you like and keep them.

One thing you should have in mind is, you should never over stock your tank with crabs because they need enough space to be healthy.

So calculate the size of your crabs and know how many to keep in this type of tank and they will still have enough space.

Personally, I won’t advise keeping more than 5 crabs of medium size in this type of small tank.

Crayfish: can live In 20 Gallon Tank

Just like crabs, Crayfish is also in the family of crustacean.

They are very much like crabs and are almost the same size with them too.

So you can actually stock them in a 20 on tanks if their natural habitat are replicated.

They’re aggressive and so don’t need much of other species of animals, so keeping them alone with their kind is the ideal or you can research and find out some other smaller animals they could be comfortable with and keep them with them too.

Normally, I would advise not having more than 5 crayfish in a 20 gallon too, especially if there are other smaller tank mates there.

Betta fish: can live In 20 Gallon Tank

Is a great option for this type of tank.

They are very fine fish and colorful and normally makes great beauty for room aquariums.

Related: Which Aquarium Pets could live in a 2 gallon tank?

Although they are small and could only get to 4 inches in size, but they are very lively fish that loves to swim about I’m their tanks.

So they need enough space to do that, and a 20 gallon is very perfect for a few of them to swim or move about comfortably and Peacefully.

You can keep up to 3 of this fish in a 20 gallon and also add snails for them or even other tiny bottom dwellers, and they will still be ok.

So a 20 gallon is quiet okay for some random smaller animals like the Bettas.

Frogs or Toads: can live In 20 Gallon Tank

Another pet you can keep in a small tank like the 20 gallon tank is either frog or toads.

There are many species of these two animals and they vary in sizes, so if you’re a fan of these animals, I would advise you to choose a particular specie and stick to them.

For instance, if you want to keep a group of Africa dwarf frogs or bull frogs etc, then stick to each specie and keep a few of them in order not to over crowd the tank.

Then if you’re not entirely okay and there are still enough space in the tank, then look for their suitable tank mates and add them there too.

Normally, I won’t recommend having more than 4 African dwarf frogs in a 20 gallon, for the sake of space, because they love jumping about.

Angelfish: can live In 20 Gallon Tank

Angel fish as the name portrays are fine fish to keep in the home aquarium.

They are peace and so have so many suitable tank mates you can keep with them.

They can get to the size of 10 inches, although there are other smaller species that could only grow up to 3 inches.

Related: Tank sizes for different numbers of Angelfish

So you need to check you Angelfish size, then calculate and know how many you should be able to keep in a 20 gallon and they will still be very comfortable in it.

Also if you like, you can compliment them with some other various suitable types of animals that could still fit in the tank too.

You should try as much as possible to avoid keeping bigger Angelfish in such a small tank, instead, look for more smaller ones or better kept the juvenile ones in this type of tank, till they mature, then change their tank.

I would recommend having up to 4 of the smaller ones in a 20 gallon tank.

Neon Tetras: can live In 20 Gallon Tank

Neon Tetras are small beautiful fish that could only grow up to slightly 3 inches in size.

They are peaceful and are very perfect for so many tank sizes, including 20 gallon tank.

When keeping this type of fish in a tank like the 20 gallon, then keep them in a group of about 4-5 and they will be okay.

Related: Tank sizes for different numbers of Neon Tetras

Keeping a group of Neons in a 20 gallon tank which comprises about 16-18 fish is okay, and could be supplemented with other smaller animals if you want.

Shrimps: can live In 20 Gallon Tank

Shrimps have are in the family of crustacean and look more like crayfish.

They have many species, including the dwarf and the more bigger ones.

With such a small tank like the 20 gallon, I won’t recommend keeping the bigger sizes too many in this kind of tank, except for the dwarf types.

The dwarf Shrimps originated from Taiwan and their ideal temperature is 59-84°F

The males could reach a size of 1.30 inche, while the females could only reach a size of 1.5 inche or a little bit more.

So judging by their size, these creatures are very tiny animals and dozens of them could easily fit in a 20 gallon tank and live very comfortable in it.

Shrimps are not know to produce toxic or dirty aquarium water so quickly, so they’re perfect match for this type of fish tank, and you can keep them up to 15-20+ in a 20 gallon tank without any issue, for the fact they have live plants in the tank.

Although they don’t easily dirty a tank water, but make sure you clean their tank and change water, at least once or twice a month, especially when they’re many in a small tank like the 20 gallon tank.

Snails: can live In 20 Gallon Tank

If you want to buy a Small tank like a 20 gallon tank, and you’re wondering what you can possibly have in such a tank, then snails are good option for you if you’re a fan of Snails.

When I made mention of snails, there are many species of snails, Bigger species like the Apple, Mystery snails etc could be kept in this tank in their numbers.

We all know that snails are agents of tank purification and will eat dead and decaying plants, foods and any fungal or insects that die in the tank and might pollute and harden the water if not removed.

This is one of the reasons why keeping snails is cool.

So all species of Snail are very perfect for 20 gallon tank and avoid mixing incompatible species together. ( check our other articles about snails to know which specie is compatible with each other)

Infact any specie of snail is a good match for this type of tank, for the fact they don’t reproduce so fast and so quickly, thereby overcrowding the tank.

Even if they do multiple so quickly, you can always keep their population in control. ( we have an article about that too)

Normally, every animal need enough space in it’s environment, so if you’re to keep bigger species of snails like the mystery snail, then you have to check their size and calculate their tank space in order not to overcrowd them in a small tank like the 20 gallon and try to upgrade the tank when they grow in population, so that they will still be comfortable.

Seahorse: can live In 20 Gallon Tank

If you want to buy a 20 gallon or you already have one and you are thinking of what to keep in it, then seahorse is a great option if you love and could care for them.

We all know that seahorse are huge animals, but there are some species that could be very small in size.

Such species includes dwarf or Pygmy seahorse as the case may be, are the perfect animals to be kept in a 20 gallon tank.

They need enough space to swim about, so keeping them in small number that is very suitable to your tank size is the ideal for keeping them healthy and happy.

Also you could compliment them with other suitable animals that could fit nicely in the tank too.

Tank Requirements

We all know that fish keeping is not all about getting a tank and putting in some random aquatic animals in the tank and feeding them.

There are some requirements that the tank needs to be okay and habitable for any animal that live in it. They are:

  • Heater
  • Filter
  • Air pump
  • Substrates/gravels/caves
  • Live plants
  • Water testing kits
  • floating plants/islands


So you see, a 20 gallon tank is still very useful.

Although you can still research about other possible aquatic animals that could live in this kind of tank.