How Many Glofish in a 5-gallon Tank

If you own a fish tank you may be looking to purchase some colorful fish to put into your tank. You may have come across a specific breed called glofish. 

These fish are brightly colored and fantastic to look at. Glofish can be a great addition to household aquariums. But how many glofish can you keep in a five-gallon tank?In this article, we will be going into detail about how the glofish originated, how many you can put in your tank, and the kind of species they can live with.

What are Glofish?

Glofish are genetically modified breeds of fish. They are a species that do not occur naturally in the wild. The first glofish were created using zebra danios that were taken by scientists and inserted with a fluorescent gene. Over time more species of fish have been made into glofish, such as barbs, tetra, and rainbow sharks.

Glofish comes in a variety of different bright colors, such as:

  • Green
  • Red
  • Pink
  • Purple
  • Blue
  • Orange

In terms of size, this varies depending on the type of glofish you choose. Tetras and danios are a lot smaller in size and reach around two inches. Depending on the barb they may grow slightly bigger than this. Rainbow sharks are a lot larger and over time will take up a significantly larger portion of your tank. They will reach around six inches

What Fish Can Live With Glofish?

What can live with glofish is dependent on the breed of glofish you choose.


Danios are schooling fish that are non-aggressive. They can be kept with other community fish such as tetra, platy, and mollies.


Tetras are another breed that is schooling and non-aggressive. They can be kept with other community fish such as guppies and danios. 

We would not recommend putting tetras in a tank with larger, aggressive fish like the angelfish.


Barbs are a little bit more tricky to keep. While they are schooling fish, they can be fairly aggressive, especially if you only have a couple in a tank. We would recommend a group of around six or more barbs in a tank. 

It is best to keep barbs with larger fish that will be able to fend off bullying. If you have any fish with fancy tails such as a betta and guppies, barbs are not recommended. 

They are notorious for being fin nippers. As a result, it is best to keep them with larger fish, such as plecos and corydoras.

Rainbow Shark

Out of all of the glofish types, rainbow sharks are the most tricky to care for. While they are low maintenance, due to their size and aggressive tendencies, you need to be careful when choosing their tank mates.

You should only have one shark per tank. If you place two sharks in a tank together, they will fight and potentially kill each other. It is not recommended to place a shark into a tank with smaller fish such as tetras. As they grow they will likely bully and eat smaller fish.

In addition to this, any fish with a fancy tail should be avoided as your shark will likely attack it. We would recommend fish such as gourami and larger species of the barb.

How Many Glofish Can You Put in a 5 Gallon Tank?

A five-gallon tank is relatively small and as a result, you will be limited with how many glofish you can keep in it. You will also need to bear in mind the existing fish you have in your tank, and adjust the number accordingly to suit this.

As danios, barbs, and neons are all schooling fish, it is not recommended to purchase them individually. This will need to be taken into consideration because you should purchase at least 6-8 of the species for a good school. 

With this in mind, while you technically may be able to put a few of these fish into a 5-gallon tank, it does not mean you should if it compromises the school.


Danios are fast-swimming fish. Although they are small in size, they do require a lot of swimming room. Given this, you would only be able to have around 2-3 danios in a 5-gallon tank, which is not enough fish for the school they require.


As Tetras are typical a little slower than danios, you would be able to put a few more of these in a 5-gallon tank. We would not recommend putting more than around 6 tetras into a tank of this size if they are the only fish in the tank.


As barbs tend to grow a little larger than danio and tetras, realistically you would only be able to keep around 1-2 barbs in a 5-gallon tank. This is not enough room to have a school and therefore we would not recommend this.

Rainbow Shark

A rainbow shark is far too large to keep in a 5-gallon tank. They will outgrow a tank of this size almost instantly. They require a lot of space to swim and you will need a tank of at least 30 gallons for it to live comfortably.


Although Glofish are fantastic fish to keep, they do require a significant amount of space. In theory, the smaller Glofish are small enough to be housed in a 5-gallon tank, but in practice, this is not recommended. 

As the smaller Glofish are schooling breeds, they must be kept in large groups of their species. If you do not put enough of the species into the tank, the fish will not have a good quality of life. Rainbow sharks require a much larger tank and are not suited to only 5-gallons.

Although Glofish are a lovely breed, care must be taken when choosing them. If you are interested in this breed, we would recommend purchasing a larger tank. 

While you can potentially keep a small school of tetras in a 5-gallon tank, this is not recommended. A tank that is at least 30 gallons would be a much more suitable option for Glofish.

We hope this article has helped educate you on this beautiful species of fish!