How Many Glofish Tetras In 10, 20, 30 Gallon Tank?

how many glofish tetras

People share the same kind of opinion about one of the common fish sorts, the Glofish Tetras. They prefer the Glofish Tetras, but they stay in a dilemma regarding schooling them in a different gallon tank after or before choosing them. So, to make things easier, I will be helping you to know how many Glofish Tetras should be in 10, 20, and 30-gallon tank.

To respond- you can keep a maximum of 4-5 Glofish Tetras in a 10-gallon tank. However, 4 Glofish Tetras are best in a 10-gallon tank, but 5 is the maximum that you can have. On the other hand, 5-6 Glofish Tetras are suitable in a 20-gallon tank. And Approximately 9 Glofish Tetras are best in a 30-gallon tank.

But before getting into the detailed information of Glofish Tetras in 10, 20, and 30 gallon tanks, here is what you shouldn’t miss.

The Glofish Tetras

Generally, the Glofish Tetras grows maximum up to 2.5 inches only. It requires 72 to 82 degrees Fahrenheit (22 to 27 degrees Celsius) temperature. It is a peaceful fluorescent fish that does not require extreme care level.

Moreover, the Glofish Tetras are easy to keep as they are not aggressive like other Glofish species. Also, remember to keep them in a group as they are schooling fish. Usually, the group of at least 5 Glofish Tetras is quite suitable though you can opt for more as per the size of the tank. They stay better when kept in a group.

That’s why the number of Glofish Tetras in different gallon tanks is essential to decide.

General Rule To Know Before Keeping Glofish Tetras In Gallon Tank

Firstly, it is significant to know the basics of keeping Glofish Tetras in various gallon tanks. The base to acquire is the optimal size of the Glofish Tetras. They grow on an average of 2 inches to a maximum of 2.5 inches. The size of the Glofish Tetras determines how many of them can get into different gallon tanks together.

Besides, the golden rule or general rule of thumb also explains the range of fish size in particular gallons of water. Thus, the general rule of thumb is essential to learn while thinking of Glofish Tetras in your tank.

According to the broadly known golden rule, a fish of 1 inch requires 1 gallon of water to survive.

Here, the Glofish Tetras grows an average of 2 inches to 2.5 inches. So as per the rule, a usual Glofish Tetra requires at least 2 gallons of water at a minimum. Plus, if your tank has slight decorations, then it may need 3 gallons of water.

Similarly, if talking about the maximum average size of a Glofish Tetra that is 2.5 inches, it requires around 3 gallons of water.

How Many Glofish Tetras In 10 20 30 Gallon Tank?

As we know, the size of the glofish tetra is 2.5 inches. Hence, to keep a group of five Glofish Tetras in the tank, you would need at least 10 gallons.

The Glofish tetra fish need to be kept in a group of at least five or more due to their schooling nature as they live better when swimming with other like-minded fishes.

Now, this is just a layer of information about the number of glofish tetras in 10, 20, and 30 gallon tanks.

Let’s talk in detail about Glofish tetras in 10, 20, and 30 gallon tanks respectively.

Glofish Tetras In 10 Gallon Tank

A 10-gallon tank for the Glofish Tetras isn’t fully adequate but possible. If you indeed want such eye-catching Glofish Tetras but have less space for managing the aquarium, then you can opt for a 10-gallon tank for them.

However, as per the general rule of thumb, a fish of 2.5 inches requires around 3gallons of water. But in reality, not all the Glofish Tetras grow fully to their maximum size.

Most of them do increase only up to 2 inches in their complete lifetime. So 2.5 inches is the average supreme size that a Glofish Tetra can grow. That’s why you can have 5 Glofish Tetras in a 10-gallon tank.

Still, if you are unsure about the maximum growth of Glofish Tetras, you can go for 4 of them only in the 10gallon tank.

Similarly, if you are thinking of any decorations in it, then don’t overdo it. Again, the tank is not big enough for immense decorations, and Glofish Tetras may not live finely.

Glofish Tetras In 20 Gallon Tank

The 20-gallon tank is quite big. The Glofish Tetras will get enough space to swim and thrive better.

In the 20 gallon tank, you can maintain a group of 5-6 Glofish Tetras. If you follow the golden rule over here, you may think for up to 8 Glofish Tetras.

But let me remind you that a tank for Glofish Tetras doesn’t consist only of them. Some decorations and plants are essential to comfort your Glofish Tetras as they can get shy in the beginning.

Also, leafy plants are necessary for the tank with glofish. But be careful while decorating because too much of it can consume a lot of swimming space.

This tank size can help your Glofish Tetras to thrive finely and live well. Thus, you can get 5-6 Glofish Tetras in a 20gallon tank with full certainty.

Glofish Tetras In 30 Gallon Tank

A 30-gallon tank is significantly significant for Glofish Tetras. Here, you will get enough space to have up to 9 of them in the tank at a time.

But as per the general rule, they need around 30 gallons of water and grow on an average length of about two inches or more than that (which is the reality).

So, if you want to maintain a group of 10 to 12 Glofish Tetras in this tank, then your glofish tetra fish would need around 30 gallons of water.

Moreover, there should be no other decoration or plants that can hamper their swimming space. In such cases, where they are kept in a big tank, they may not grow to their full size.

Therefore, if you want them to be happy and healthy, the tank must have only Glofish Tetras with no other plants or decorations.

You can keep 12-14 of them here without any worry, as this space will help them thrive better.

Avoid Overcrowding The Gallon Tank – Grasp Why?

This is an important question that many people have been asking. It might sound like a no-brainer, but overcrowding the tank for Glofish Tetras can be really dangerous and even fatal at times.

People do not understand the potential for infections to arise from overcrowding, which can be very serious if it occurs in small tanks like this one.

A crowded environment leads to aggression and results in poor health. The overcrowded Glofish Tetras can also lead to the spread of infections, which increases their chance of contracting diseases.

Leads To Aggression

It might be difficult to believe, but overcrowding Glofish Tetras leads them to aggression.

When they cannot have enough space and live in an environment where others are invading their territory, it can result in aggressive behavior such as fighting or chasing each other around the tank, which puts stress on both themselves and the other inhabitants in the tank.

Results In Poor Health

Overcrowding of Glofish Tetras also results in poor health for them, as they cannot take care of their needs, which can result in infections or disease outbreaks that might be difficult to control if left untreated.

Can You Put Glofish Tetras In Smaller Than Gallon Tank?

So, you might be wondering if it is possible to put them in a smaller tank.

Yes and no! Glofish Tetras can live in small tanks, but they need at least ten gallons of water which means that you would have to get two or more five-gallon bowls for your aquarium to live comfortably.

Difficulties For Glofish Tetras In Smaller Tanks

It is not uncommon for Glofishes to be kept in tanks as small as a gallon. The question of how many Glofish tetra fish can live in this tank size usually arises, and it may come with the argument that if they are given enough food, then there should be no problems.

This is not the case because Glofish Tetras are schooling fish, and they thrive in groups of six to eight. This means that if you keep them in a gallon tank, there will be less than three or four on average. They need more space for swimming around and exploring their environment, which could lead to aggression from restricted space and poor health.

It is important to keep the tank at least ten gallons for Glofish Tetras to have enough space and avoid overcrowding. This will allow them to live a long life in comfort, without having any negative effects from an environment that thrives on aggression or poor health due to lack of necessary care.

Frequently Asked Questions:

Do Glofish Tetras Require Aquarium Heater?

Yes, the Glofish Tetras require an aquarium heater. They need warm water to simulate like natural habitat in the aquarium. Here they require 72 to 82 degrees Fahrenheit of water temperature. Therefore, it is significant to get an aquarium heater to maintain the temperature firmly in the aquarium. It will make the Glofish Tetras stay active and well.

Can Glofish Tetras Live Alone?

The Glofish Tetras are schooling fish that has to stay in a group of at least 5 of them. So, if you place the Glofish Tetra alone, it becomes difficult for them to live as they tend to stay in a group. Also, they are social and peaceful fish, so they are easygoing with suitable tank mates too. But solely living is not their thing. So, the Glofish Tetras cannot live alone.

What Are The Best Tank Mates For Glofish Tetras?

As the Glofish Tetras are pleasant fish with other species, considering some tank mates is a great idea. So, some of the best tank mates for Glofish Tetras are:

  • Neon Tetras.
  • Black Neon Tetras.
  • Cardinal Tetras.
  • Danios.
  • Guppy.
  • Tiger Barbs.
  • Discus Fish.
  • Hatchet.
  • Swordtail etc.


In conclusion, Glofish Tetras are omnivores, schooling fish that prefers to be in groups of six or eight. Keeping them in a tank size smaller than ten gallons will lead to aggression and poor health issues. They need space for swimming around, exploring their environment, which would otherwise result from overcrowding the small tanks they’re kept in. In addition to this, they should be kept in a tank size of ten gallons or more as this will allow them to live for a long time with comfort and without any negative effects.

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