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How Many GloFish in a 3 Gallon Tank? (Answered)

Your aquarium will look wonderful and attractive with glowing GloFish. GloFish look different from ordinary fish, they are small in size and look incredible. However, even though they are small, they require special care. 

Therefore, it is important to know the maximum number of Glofish that can be kept in a gallon of water.

How many GloFish in a 3-gallon tank?

The general rule of thumb when keeping Glofish in an aquarium is to keep one inch of fish in one gallon of water. This means that a 3-gallon tank can hold a maximum of three Glofish. Keeping more than 3 Glofish in a 3-gallon tank will reduce their lifespan and health.

The fish in our aquarium are our loving pets. Keeping them healthy and beautiful is our responsibility. But the rule of keeping a Glofish per gallon of water is not always applicable.

Glofish come in a variety of sizes. They can range between one inch and three inches in size, depending on the age. A one-inch-long Glofish can survive in a gallon of water, but a three-inch Glofish cannot survive in a gallon of water. 

Therefore, each inch of Glofish should have a tank of at least one gallon. It will not be a problem, however, if it is more than that.

Glofish Danios:

Glofish Danios are known for their vibrant colors. They come in a rainbow of colors, and their bright colors make them easy to spot. However, their behaviors are very unpredictable. For more mobility, keeping a lot of Glofish together is not recommended. 

Glofish Danios are usually 2 to 2.5 inches in size, which is relatively large. For this reason, you will need more space. It is recommended to keep at least five Glofish Danios together since these are schooling fish. You will need at least a 10-gallon tank for five Glofish.

Glofish Tetras:

Glofish Tetras can grow up to 2.5 inches long. As a juvenile, they are about 2 inches long. It is okay to keep two Glofish Tetras in a five-gallon tank. They can live in such a small tank. 

It is recommended that you do not keep more than one Glofish Tetra in a tank that is less than 3 gallons. These are schooling fish, so no less than five fish should be kept together. If that is the case, you will need to upgrade the tank.

Can GloFish live in a 3-gallon tank?

The young Glofish have a small size, so they require less space. A Glofish of one inch can survive very well in a 3-gallon tank. Despite this, as they can be as large as 2-3 inches, 3-gallon tanks are not suitable for them. Glofish can live in 3-gallon tanks if their size is 1 inch

However, if their size is larger you will need to upgrade the tank.

Can 2 GloFish live in a 3-gallon tank?

A Glofish that is one inch in size can live in a 3-gallon tank. A maximum of three Glofish can be housed in a three-gallon tank. If the Glofish is around 1 inch in size, then two Glofish in a three-gallon tank will feel cramped. 3-gallon tanks are not suitable for two adult Glofish.

How many GloFish in a 3.5-gallon tank?

The maximum amount of Glofish in a 3.5-gallon tank is three. Glofish with an inch in diameter can live well in a gallon tank, but if its size exceeds two inches, experts recommend keeping only one in 3.5 gallons. You can keep no more than two 2-inch Glofish per 3.5-gallon tank.

Can GloFish live in a small tank?

Keeping Glofish in a small tank can be uncomfortable for them. Keeping too many Glofish in a small container can seriously hurt their health. Glofish is our loving pet, we do not want them to mourn. Glofish in small tanks may survive, but their lifespan and health will deteriorate.  

What is the minimum tank size for Glofish?

Glofish requires a larger tank than ordinary fish, so a three-gallon tank is a minimum size for Glofish. Fish cannot live normally in tanks smaller than this. And the maximum number of Glofish you can keep in the three-gallon tank is 3.

How to keep and care GloFish in a 3-gallon tank?

Glofish are fascinating to observe because they are so active. Thus, keeping them in a small space like a 3-gallon aquarium is not a good idea at all. If, however, you are already keeping them in a 3-gallon aquarium, you should take extra care.

Maintain an appropriate temperature:

Glofish need the right temperature to survive. For Glofish danios, the temperature is not a factor, but for other Glofish, the temperature should be at least 72 degrees Fahrenheit. The temperature should, however, not exceed 80 degrees Fahrenheit for Glofish.

Changing water continuously:

It is necessary to change the water in a small aquarium regularly since glofish cannot live in it. As you cannot set up a plant in a 3-gallon tank, you need to change the water frequently and vacuum the gravel. 

Glofish can easily live in a small tank if the water is changed frequently. Consequently, you must pay extra attention to whether the filter is functioning correctly.

Less Fish:

Keeping much fish in a three-gallon tank poses health risks due to its small size. Keep as few glofish in your tank as possible. Taking care of it will be easy, and health will be good as well.

Great Food:

Glofish can adapt to a variety of foods. Therefore, there is no need to worry about food. Whether it is frozen food, flake food, or pallet food, they will continue to digest properly. 

How to set up GloFish 3 gallon tank?

Let’s walk through the following steps that might help you to set up glofish 3-gallon tank –


It is very important to clean the Glofish tank properly before using it. They may have dust and germs inside. First, open the cover and soak it in water. Let the tank dry.

Filter setup:

A filter controls the water flow in the tank. Since glofish are small in size, the mobility of water in the filter needs to be kept to a minimum. The filter switch will be found on the side of the tank. Turn it down if necessary.

Putting Gravel:

Glofish gravel is appropriate for use in a Glofish tank. However, they come in a very dirty condition in the packet. Wash them with water first, then put the gravel in the tank. You need to remove the gravel around the filter hole on the bottom of the tank.

Setup Filter Cartridges and Heater:

Before installing, make sure the cartridges are thoroughly cleaned. Then install the cartridge in the filter chamber. Next, install the heater in a tank of a certain size. If you want to set up a plant, remove the gravel and plant it carefully.


It’s almost time for the tank to start. Place a cup on the gravel and slowly pour water over it. Do not allow excess water to accumulate on the scale of the tank. Your GloFish Tank is now ready to use.

Final Thought

As we have mentioned, each inch of Glofish requires at least 1 gallon of water. However, the minimum tank size should be 3 gallons for your Glofish. Remember that, an aquarium of 3 gallons can hold a maximum of three Glofish. But larger tanks are more suitable for them.