How Many Glofish In A 10-Gallon Tank? Zero?

Dec 27, 2021

How Many Glofish In A 10-Gallon Tank

I was astounded to find the extent of misinformation the internet is littered with when it comes to raising glofish. I mean, even the official site is full of misleading info. For instance, the largest glofish tank listed on their site has a 10-gallon capacity, all the while they sell hyperactive danios and aggressive rainbow sharks. So, how many glofish in a 10-gallon tank? Is it even possible?

Let’s find out the truth. 

How Many Glofish In A 10-Gallon Tank?

You can keep 5-6 glofish tetras, 3 female glofish bettas, and 4-5 glofish danios in a 10-gallon tank. But glofish barbs and glofish sharks aren’t suited for tanks this small. 

As you can see, the fact that the largest tank size advertised for glofish is 10-gallons is problematic. Not all glofish varieties can go inside a 10-gallon tank.

How Many Glofish Tetras In A 10-Gallon Tank?

Credits: Robert Kamalov (Creative Commons license)

Glofish tetras are genetically modified black skirt tetras. So, schooling is a natural instinct for these fish. You can keep around 5-6 glofish tetras in a 10-gallon tank and observe their unique schooling behavior. 

However, if you’re confident about your fishkeeping skills, you can go a little overboard and add up to 8 glofish tetras in a 10-gallon tank. But remember, overstocking means you have to stay on top of water quality all the time. 

We can use the ‘one inch per gallon’ rule for small and peaceful fish like tetras that don’t get over 3 inches long. But note that this rule is somewhat controversial as it doesn’t consider the room taken by decors and substrate. 

So, a glofish tetra’s average length is 2 inches. And when we divide 10 by 2, we get 5. 

According to this rule, the number of glofish tetras you can keep in a 10-gallon tank is 5, which resonates with the answer shared by several hobbyists shared on different forums. 

How Many Glofish Danios In A 10-Gallon Tank?

Glofish danios don’t grow too big. They barely get over 2 inches long. However, they’re super active and love to dart around the tank. So, you can only keep 4-5 glofish danios in a 10-gallon tank. 

However, if I were to give you my honest opinion, I wouldn’t advise keeping them in a 10-gallon tank. A 15-gallon long tank is the bare minimum requirement. 

A 10-gallon tank simply doesn’t have enough room for these fish to swim and race in. If possible, go for 20-55 gallons. Also, keep in mind that they need a long tank over a tall one. 

From what I have read on forums, hobbyists strongly oppose keeping hyperactive glofish danios in a 10-gallon tank. 

How Many Glofish Barbs In A 10-Gallon Tank?

Unfortunately, you can keep precisely 0 glofish barbs in a 10-gallon tank. Although these fish don’t grow too big (3 inches), they are mean and territorial. So, 20 gallons is the absolute minimum size required. 

However, I’d recommend getting at least a 30-gallon tank as these fish are incredibly active swimmers. And they should at least be kept in a group of 4 to curb their innate aggression. 

How Many Glofish Sharks In A 10-Gallon Tank?

Credits: Ccm272 (Creative Commons license)

You can’t even possibly think of keeping a glofish shark in a 10-gallon tank. The recommended tank size for a single glofish shark is 50 gallons. And if you want to keep multiple of them together, you should at least get a 125-gallon tank. That being said, bigger is always better. 

These fish grow the largest in the glofish family – getting up to 6 inches long. On top of that, they are super active and territorial. If the aquarium is too small for their liking, they will become highly hostile towards fellow tankmates. 

How Many Glofish Betta In A 10-Gallon Tank?

If you are looking to raise male bettas, you can only add 1 of them in a 10-gallon tank. If you add any more than that, you will end up with injured or potentially dead fish. However, if you’re adding females only, you can add around 3. 

That being said, I’d recommend allocating at least 5 gallons each for one betta fish. These fish are called ‘Siamese fighting fish’ for a reason. They can get super territorial and resort to violence if they don’t have enough space. 

Recommended Readings!

How Big Do Glofish Tetras Get? Grow Them Fast!

What Do Glofish Eggs Look Like? Photos And Videos!

How Many Glofish In A 3-Gallon Tank? Zero!

How Many Glofish In A 10-Gallon Tank? Real Answers By Real People 

In an effort to provide you with well-rounded and genuine information in a single platform, I have collected the responses shared by real hobbyists on keeping glofish (or their non-modified cousins) in a 10-gallon tank.

Here’s what they look like:

“I first started out with glofish in a 10-gallon tank, and now I am moving to 20 gallons. These fish aren’t big. But they are so active that they really need plenty of room. Mine can start to nip each other.”

“You can get away with keeping 7-9 glofish tetras in a 10-gallon tank. But I wouldn’t keep any danios as they are too active and need more space.”

“I would get a 20-gallon tank instead of a 10 if you haven’t already bought it. Bigger tanks are always easier to manage than small ones.”

“Get a bigger tank. That way, you can get a school of tetras (6) and a school of danios (5), and there would be plenty of room for all of them. Just make sure the tank is fully cycled.”

“I will suggest a 20-gallon long or a 30-gallon long tank for glofish danios as these fish need more horizontal space than vertical.”

“The thing about glofish danios is they really like to swim – so, the longer the tank, the better. Note that a 20-gallon tank comes in 3 sizes: long, tall, and extra tall.”

“A 10-gallon tank is really unsuitable for a rainbow shark, even a juvenile one. The fish will become stunted very quickly. It could lead to long-term health problems and a reduced life expectancy.”

“If you are keeping male bettas, then only one. If you want females, you can keep 4-5. No more, no less.”

“I’d say about 4 female bettas. But make sure they have plenty of hidey-holes. But whatever you do, DON’T PUT MALES TOGETHER UNLESS YOU WANT DEAD BETTAS.”

“You cannot have more than one male betta in a tank that is not divided. It does not matter how big the tank is. They will eventually find each other, and the result won’t be pretty at all.”

The Risks Of Keeping Glofish In A 10-Gallon Tank

A small tank can stunt a fish’s growth and deteriorate its health due to stress and polluted water. Also, your schooling glofish like tetras and danios will simply not school in a 10-gallon tank. 

Even though glofish are often advertised to be suited for small tanks, it isn’t really the case. For instance, a single glofish shark requires at least 50 gallons to live comfortably.

Stunted Growth 

Researches have shown that fish release certain pheromones into the water that can inhibit the growth of other fish of the same species. These studies mainly focus on fish from the carp family, like goldfish, but we can’t rule it out for other species as well. 

These pheromones will get diluted and swept away quickly in a bigger tank. 

But in small tanks, the concentration of these chemicals in the water will be significantly high. And when fish absorb this water into their bodies, their growth can be possibly stunted. 

Likewise, a small tank also means a lack of enough activity and exercise. And while the negative impacts may not be observed right off the bat, it wouldn’t be farfetched to link lack of exercise with stunted growth. 

Aggression And Stress 

Glofish tetras are schooling fish that find safety in numbers. Glofish danios are hyperactive fish that need plenty of space to dart in. Glofish bettas don’t mind fighting to the death over a territorial feud. 

Glofish barbs are aggressive and highly hostile if they don’t have enough room to live in. And lastly, a single glofish shark requires at least 50 gallons. 

So, the truth be told, small tanks are really not ideal for any glofish species. It will only fuel their aggression and stress, which in turn will compromise their immunity and make them prone to diseases. 

Even worse, the fish may fight to the death. 

Polluted Water 

Small tanks are often marketed as the perfect starting point for beginners. They usually come with taglines like ‘beginner-friendly’ and ‘low-maintenance’. But these are nothing but gimmicks. 

A small tank only means one thing – a small room for mistakes. Hear me out. The same amount of leftover food in a small tank would pollute the water more quickly than in a big tank, isn’t it? 

Also, even the slightest fluctuation in water parameters can be felt quickly throughout the tank – profusely stressing the fish. 

With small tanks, you will end up doing more water changes and using more elbow grease to ensure a safe and healthy environment. 

No Schooling 

Glofish tetras, barbs, and danios are schooling fish. They’re hardwired to move in schools. To put it simply, they will not be able to thrive and live happily in any number less than 5 or 6. And a 10-gallon tank isn’t big enough to house that many. 

This will massively stress them out. As a result, they will lash out at each other – nip fins, bite, and even kill. 

Frequently Asked Questions 

How Many Glofish In A 1.5-Gallon Tank? 

You can keep 0 glofish in a 1.5-gallon tank. None of the five glofish types – tetras, barbs, danios, bettas, and rainbow sharks – would fit in a 1.5-gallon tank. 

Technically, you can fit 1 glofish tetra in it, but since they’re schooling fish, you should ideally keep them in a group of 6 or more. And that’s not possible in a 1.5-gallon tank. 

How Many Glofish In A 5 Gallon Tank?

You can keep 3 glofish tetras and 1 glofish betta in a 5-gallon tank (not together). Even though small, glofish danios are extremely active fish – so, a 5-gallon tank isn’t ideal for them.

And as you have already guessed, a tank that small is nowhere near suitable for even a single glofish barb or shark. 

How Many Glofish In A 8-Gallon Tank?

You can keep around 4 glofish tetras, 3 glofish danios, 2 glofish bettas, and 0 glofish barbs and glofish sharks in a 10-gallon tank (not together). Even though you can fit some of these fish into an 8-gallon tank, it’s really not ideal. 

It’s best that you upgrade your tank. 

How Many Glofish In A 20-Gallon Tank?

You can safely keep 10 glofish tetras in a 20-gallon tank. If you are confident about your fishkeeping skills, you can push it to 20. As for glofish bettas, you can keep around 4-6 (all females). A single glofish barb needs about 4 gallons of space. So, you can house around 5-6 of them.

Glofish danios are schooling fish and are super active in the tank. So, you can safely keep around 10-12 of them in a 20-gallon tank. 

Unfortunately, you can’t fit any glofish shark in a 10-gallon tank since they require a minimum of 50 gallons for a single fish. If you plan to add any more than one, you should at least get a 125-gallon tank. 

And as I always say, the bigger the tank, the better. 

Final Words: How Many Glofish In A 10-Gallon Tank?

A 10-gallon tank isn’t that big, to begin with. It is only 20 inches long, 10 inches wide, and 12 inches tall. So, even though these tanks are billed as beginner-friendly, they aren’t. 

So, we don’t recommend keeping any of the 5 glofish species in a 10-gallon tank. 

However, technically, you can keep 5-6 glofish tetras, 3 female glofish bettas, and 4-5 glofish danios in a tank with a 10-gallon capacity. 

However, glofish barbs are schooling fish with an aggressive disposition. So, a 10-gallon tank would never be sufficient. And for glofish sharks, you need to allocate 50 gallons each for an individual fish. 

Recommended Readings!

How Long Do Glofish Live? Which Glofish Species Lives Longest?

How Many Glofish In A 20-Gallon Tank? Honest Answers!

How Long Can Glofish Go Without Food? Which Species Can Go The Longest?

How Big Do Glofish Get? What Tank Size Do They Need?

rohit gurung author at urbanfishkeeping

About Rohit Gurung

My never-ending love and fascination with Aquascaping started when I received a red-eared turtle for my 10th birthday.

Apart from researching and writing, I spend hours gazing at my 3 turtles. And yeah, I bask alongside them too.