How Many Glofish In A 5 Gallon Tank?

Are you planning to bring glofish to your aquarium? And the most confusing part is how many Glofish in a 5 gallon tank? Glofish with its fluorescent body and bright, vivid colors have attracted the attention of a majority of aquarists.

This fish has a vast fandom, and almost every hobbyist wishes to keep this pretty creature in the fish tank at home. The school of glofish moving around in the aquarium waters with their rainbow hues is such a treat to the eyes. 

Who doesn’t like to have eye-soothing lovely fishes with sweet body colors of yellow, pink, and blue swimming around inside the fish tank? As much as you aspire to introduce the bright school of glofish in the aquarium, you probably stay confused about how many of them you should add to the fish tank? 


To help you sweep away all sorts of confusion from your mind, we have come up with this guide that will tell you how many glofish in a 5 gallon tank you can keep. Oh, wait! Here, we will also share some helpful tips and vital information that will help you take proper care of your dear glofish. 

But, before answering your questions, we would like to share some interesting bits of info about this bright fish. 

How Did Glofish Come Into Existence?

Glofish is a highly popular fish in the aquarium trade and is endowed with the unique characteristic of bioluminescence. This implies the ability of the fish to produce its natural light.

No doubt, it has become one of the most demanding fishes among hobbyists because of its unique nature. 

The attribute of fluorescence among the glofish is not natural. It is the result of genetic modifications performed on some common fishes by Singaporean scientists.

They wanted to experiment with bioluminescence to see if this can be a method to check the presence of toxins in the water bodies so that the lives of the aquatic organisms can be saved. 

After the research was successful, a company based out of Texas in the US named Yorktown Technologies bought the exclusive rights to conduct further research from the scientists.

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It was then that, in 2003, the very first beautiful glofish called the Starfire Red Danio was introduced in the aquarium market. The response was exploding!

Immediately, this fluorescent fish garnered attention from every fish lover and aquarist, and that is when this emerged as the most popular fish among hobbyists. 

Do you know that there are several types of glofish? These include danio, tetras, zebrafish, and barbs. They come in beautiful, rich colors of pink, purple, blue, and yellow.

When contrasted against blue or black light, the bright color of the fishes stands out and appears striking to the eyes. 

Since the glofish, in themselves, are not blessed with the fluorescence characteristic by birth, you need to be very careful while purchasing them.

This is because the gene of fluorescence is injected into the embryo of each fish so that this characteristic is automatically passed down from one generation of glofish to the other. You need to be cautious of those sellers who simply dye the fishes and claim those to be glofish.

To not get beguiled into purchasing non-healthy, fake glofish, you may have to spare a large fortune to buy them from a well-known brand. 

Glofish Tank Mates 

Since you have decided to keep glofish in your fish tank, you need to know that glofish can not adjust much with other fishes. That’s the reason why we will be suggesting you a list of glofish tank mates. Let’s see what these are!

Glofish Tiger Barbs 

Glofish Tiger Barbs are semi-aggressive. They like to move around in the waters with their mates from the same species.

Glofish tiger barbs

However, they get irked by the presence of some other tank mates. The most surprising fact about this fish is that although it growˆs only up to 3 inches in length, they have the habit of gobbling up fishes that are smaller in size than its own.

Tiger barbs behave in a friendly manner with fishes such as gourami, tetras, rasbora, rainbow fish, guppies, minnows, etc. 

Glofish Tetras 

Glofish Tetras are peace-loving creatures and tend to mingle with other fishes quite easily. The best thing about these fish is that they don’t require much space to swim.

glofish tetras

Hence, they don’t get into a fight with their co-habitants for space in the glofish aquarium or tank. They grow to only up to 2.5 inches. Glofish tetra is most compatible with angelfish, betta, danio, rasbora, guppies, killifish, etc. 

Glofish Rainbow Sharks 

A Glofish Rainbow Shark also has a semi-aggressive nature. They are found dwelling near the glofish aquarium substrate most of the time as they are bottom feeders by nature. They can grow up to as long as 6 inches.

glofish rainbow sharks

So, they need quite a good amount of swimming space in the tank. Avoid adding them to any tank that is 10 gallons or below it.

Try not to introduce any other kind of sharks in the fish tank, for it may not mingle with them well. Its tank mates include danio, minnows, gourami, barbs, etc. 

Glofish Danio 

Glofish danio

Glofish Danio is a tiny fish and grows to only up to 2.5 inches in length. If you have got a tank with abundant swimming space, danio will be an excellent fit for it. The danios tank mates include minnows, molly, angelfish, betta, tetras, pleco, hatchet, etc. 

How Many Glofish Are To Be Kept Per Gallon? 

how many glofish in a 5 gallon tank

Glofish are schooling fish, so they require tanks that offer adequate swimming space. For one glofish, 3 gallons of water is needed. To understand how many glofish can be kept in a tank, use this formula for calculation.

First, assume the maximum length to which the fish you have chosen to add to the tank will grow. Always take into consideration a bit larger figure of the fish’s length. Else, the tank will have higher chances of getting overcrowded. 

The standard rule is that any particular aquarium fish with a body length within 3 inches will require about 1 gallon of water each. While glofish tiger barb and rainbow shark require a minimum of 20-gallon tank, glofish danio and tetra fish can survive well in a 10-gallon tank. 

How Many Fish Can A 5-Gallon Tank Shelter? 

Coming straightway to your question of how many glofish in a 5 gallon tank can be kept, let us tell you that a 5 gallon tank is not at all a good choice for maintaining glofish.

It’s too little a space for the schooling fish, and they may soon contract infections, and their health condition gets affected. If you earnestly wish to keep glofish in a 5-gallon tank, it is recommended that you keep only one. 

Anyway, keeping them alone in a tank is a risky idea. The reason is that the Glofish are schooling fish and tend to swim around together in groups of 5 or 6. Long story short, avoid keeping glofish in a 5-gallon tank. 

How Many Glofish Can You Add In A Tank Of 10 Gallon? 

A tank of 10 gallons is a perfect size for keeping a school of glofish danio and glofish tetras. About 5 to 6 glofish can be kept here together.

However, a tank of this capacity is not at all ideal for keeping glofish rainbow sharks and tiger barbs as they suffer infections and feel stifled in the limited space. 

How Many Glofish Can You Introduce In A 20 Gallon Tank? 

In a 20 gallon tank, about 5 to 6 glofish can be kept. A tank of 20 gallons can support the survival of tetra, tiger barb, danio, and rainbow shark. 

Make sure that the internal environment of the aquarium is marked by the presence of an apt number of plants and other decorations. 

Don’t make the tank too overcrowded with plants and rocks; the fish won’t get much swimming space. 

How Many Glofish Can A 30-Gallon Tank Contain? 

A 30 gallon tank can contain about nine glofish. Since a 30 gallon tank is quite an enormous space, about 8 to 9 glofish can dwell perfectly in such an aquarium. 

What Is The Capacity Of A 50-Gallon Tank? 

Undoubtedly, a 50-gallon tank is sufficient to house about 10 glofish. You can also keep the glofish with its tankmates with the proper peace of mind. 

Survival Parameters For Glofish In A Tank 

aquarium with glofish

A glofish usually has a lifespan of about 3.5 to 5 years. Its survival requirements are much the same as other aquarium fishes, but just with slight variations. 

Water Temperature 

The ideal water temperature for glofish falls in the range of 72 to 82 degrees Fahrenheit. Keep a water heater for the aquarium with you so that the water stays warm and does not become too cold. 

Water pH Level 

Glofish are pretty hardy so that they can survive well in a slightly acidic environment. Strive to keep the pH level of water between 6.0 to 7.0 is going to be good enough. Maintain a pH level of 7.2 or above to ensure that the glofish can thrive correctly.

Water Hardness 

The dH level can be kept between 5 to 19. The better idea is to keep the water hardness level at 11-12. 


As its name says, Glofish loves to ‘glow.’ So it is mandatory to have proper lighting set up inside the tank. Try to use blue light as their glow becomes prominent against a blue background. 

Varieties of decorations based on blue light are now available widely, and you can quickly get these from the market. Set the led lighting in a way that the glofish receives light for about 12 hours each day. White and blue LED lights are the best options. 

Plant Decorations 

Since glofish are fond of greens and leaves, adding ferns, aquatic plants, and Anubias in the tank is a good choice. They will love to swim around the plants and hide under them. 


Feed the glofish with the flakes of tropical fish of superior quality. The glofish will be happy and healthy if you feed them tropical fish flakes two times a day. To introduce variations in the diet, you can provide them with brine shrimp once per day. 

Best Tank Options For Glofish 


Let’s see what some of the best tank options for glofish are. 

SeaClear 10-Gallon Mini-Kit 

This is a small-sized tank and can be used to keep a small number of glofish. It comes with a bunch of all the required items and equipment. The accessories add to the beauty of the tank.

You won’t get aquarium gravel with it, though. The filter that comes with the tank is quite robust and comes with a couple of plastic plants and a net.

The tank is designed to provide a built-in lighting system that is adjustable. So you can now control the intensity of light that the glofish can receive. 

GloFish Aquarium Kit Fish Tank 

This fish tank is replete with various LED lighting color options. You can choose any shade or hue that you want and enjoy watching the glow of the glofish. 

Aqueon NeoGlow 10 Gallon Orange LED Kit 

This fish tank from Aqueon comes with a good blue LED lighting system so that the vibrancy of the glofish becomes noticeable.

You also get some beautiful plants as well as gravel of bright colors with the tank. The aesthetics of the aquarium gets heightened to a great extent. 

Frequently Asked Questions (FAQ)

How many gallons does a glofish need? 

A tank with a capacity of 10 to 30 gallons is suitable for a glofish. 

Do Glofish sleep with the light on? 

No, glofish don’t sleep with the light on. Only 12-hour exposure of the glofish to light is sufficient. Maintain the pattern of 12-hour light and 12-hour darkness in the glofish aquarium. 

What is the lifespan of a glofish? 

The lifespan of a glofish varies from 3 to 5 years. 

How many glofish tetras can I put in a 10-gallon tank? 

You can put about five so that glofish tetras in a 10-gallon tank. 

About the author

I'm Gulshan, a passionate pet enthusiast. Dive into my world where I share tips, stories, and snapshots of my animal adventures. Here, pets are more than just animals; they're heartbeats that enrich our lives. Join our journey!thing.