How Many Glofish In A 30-Gallon Tank? Answers For All 5 Species!

Jan 14, 2022

How Many Glofish In A 30-Gallon Tank?

Image Credit: Ho-Wen Chen (CC License)

As popular as glofish are, they’re also equally misunderstood. They’re often perceived to be glowy fish of one particular GMO species when in reality, there are 5 different glofish species. So, the answer to “how many glofish in a 30-gallon tank?” actually depends on what glofish you’re exactly talking about.

If you’re looking for a tank that can easily fit into your sitting room yet serve as a focal point simultaneously, a 30-gallon tank would be ideal. 

This size is quite perfect for the majority of beginner fishkeepers – it’s not small enough to offer no room for mistakes. At the same time, it’s not big enough to be overwhelming to maintain. 

However, not all glofish species are suited for a 30-gallon tank. Who are they? And why? 

Let’s find out. 

How Many Glofish In A 30-Gallon Tank?

You can keep about 12-15 glofish tetras, 14-15 glofish danios, 4-6 glofish bettas, and 9-10 glofish barbs in a 30-gallon tank – Not together, of course! But unfortunately, a 30-gallon tank is still not big enough for feisty glofish sharks that need about 50 gallons each to thrive comfortably. 

Glofish sharks are highly aggressive and territorial fish. While one of them can just about live in a 50-gallon tank, you’d need an enormous tank to house multiple of them together. Even then, you can’t entirely rule out frequent duels and bloodbaths. 

But don’t get disheartened. 

As I wrote above, you can house a good number of the rest of the glofish species in a 30-gallon tank. 

Glofish tetras, danios, and barbs are schooling/shoaling fish. They find safety in numbers. 

And a 30-gallon tank would be the ideal size for a beginner to keep small schools of these fish and observe their unique schooling behavior. 

When these fish are not kept in groups, it negatively impacts their mental and physical health. 

Now, let’s look at the dimensions and tentative weight of a 30-gallon tank. 

How Big Is A 30-Gallon Tank? 

A 30-gallon tank has the following dimensions: 36” x 18” x 12” (L x W x H).

How Much Does A 30-Gallon Tank Weigh?

An empty 30-gallon tank weighs 48 lbs. When filled with water, the weight rises by around 7 times – reaching 348 lbs. 

Recommended Readings!

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

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

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

How Many Glofish Tetras In A 10-Gallon Tank? There’s Bad News!

How Many Glofish Danios In A 10-Gallon Tank? 5 Or None?

Now, I’ll answer our main query in a detailed manner. Hop on! 

How Many Glofish Tetras In A 30-Gallon Tank?

Credit: Robert Kamalov (CC License)

There are two types of glofish tetras – the standard and the long-finned versions. Both are made by genetically modifying black skirt tetras and grow around 2 inches (5 cm) and 2 ¼ inches (5.5 cm) long, respectively.

I know the ‘one inch per gallon’ rule is debatable and has one too many shortcomings. But the general consensus is that it can be safely applied to fish smaller than 3 inches. 

So, by that rule, when we divide 30 by 2 (in), we get 15. And when we divide 30 by 2.25 (in), we get 13.33. 

I also scoured through a few forums to find answers to this question.

And while I didn’t find a single thread on stocking glofish tetras in a 30-gallon tank, I found out that hobbyists mostly recommend keeping around 8-12 black skirt tetras in a 20-gallon tank. 

So, even by that standard, it’s safe to conclude that you can keep 12-15 glofish tetras in a 30-gallon tank. 

How Many Glofish Danios In A 30-Gallon Tank?

Credit: Karen Swain (CC License)

Glofish danios don’t grow very big, but boy, are they active! Glofish danios were the first-ever genetically-modified fish made from zebra danios. And if there ever was a fish Olympics, they’d surely take some medals home. 

Glofish danios are petite fish that grow around 2 inches (5 cm) long. And you know the drill – we can also apply the ‘one inch per gallon’ rule here. 

So, when we divide 30 by 2 (in), we get 15. 

As I said above, glofish danios are schooling fish. And although they won’t really school when they feel safe, 15 is an excellent number to observe this interesting but occasional phenomenon. 

How Many Glofish Barbs In A 30-Gallon Tank? 

Glofish barbs were originally created by inserting fluorescent genes into tiger barbs’ embryos. And they may have developed a bright disposition, but they have very much retained tiger barbs’ feisty demeanor. 

Much like the original species, glofish barbs grow around 3 inches (7.6 cm) long. 

And since we can apply the “1 inch per gallon” rule for fish under 3 gallons, let’s divide 30 by 3. We’d get 10. 

Glofish barbs can be mean if they aren’t kept in the right conditions. So, I wouldn’t really suggest overstocking their tank. 

That being said, understocking isn’t an option either! 

How Many Glofish Bettas In A 30-Gallon Tank? 

It’s not uncommon to see bettas being confined in a 1-gallon tank. Just because they fit doesn’t mean they should be kept there, right? The fish would lead a miserable life. 

Although the general practice is to allocate 2.5 gallons for glofish betta, I suggest allotting 5 gallons each to ensure the fish lives the best life possible. 

So, you can keep around 5-6 bettas in a 30-gallon tank. 

However, male bettas would rather prefer to be the only male in the tank. They’re the kind that even fights their own reflection. 

Therefore, if you’re planning on adding more than one male betta, you might need a tank bigger than 30 gallons. 

Or, you can consider adding a tank divider. 

Here’s one by Totuyo that’s got some great reviews. 

How Many Glofish Sharks In A 30-Gallon Tank?

Unfortunately, glofish sharks need a tank considerably bigger than 30 gallons. The minimum recommended tank size for them is 50 gallons. So, you can fit 0 glofish sharks in a 30-gallon tank. 

I know the official glofish website states that the minimum tank requirement is 20 gallons, but any experienced fishkeeper would call that bogus.

Glofish sharks were made by genetically modifying rainbow sharks. And much like their original species, they have a notorious temperament. They are incredibly intolerant of most tankmates and don’t mind bullying weaklings to death. 

If you plan on raising glofish sharks, you should at least aim to keep 5 of them together. This is to spread out the aggression, so there’s not just one poor fish at the receiving end. 

If you keep just 2 or 3, the assertive fish will chase and bite the subordinates until they succumb to death. 

Frequently Asked Questions 

How Many Glofish In A 3-Gallon Tank?

None of the glofish species are suitable for a 3-gallon tank. Technically, you can keep 1-2 glofish tetras, barbs, and danios. It’s also not uncommon to keep bettas in a 3-gallon tank. But I’d strongly suggest against this practice. 

There’s simply not enough room in a 3-gallon tank for any fish to live happily, no matter how small it is. 

How Many Glofish In A 5-Gallon Tank? 

You can keep 2 glofish tetras and danios and 1 betta in a 5-gallon tank (not together). But once again, I’d request you to get a bigger tank. Your fish would really be thankful. 

How Many Glofish In A 20-Gallon Tank?

A 20-gallon tank still wouldn’t suffice to keep a glofish shark irrespective of what the official site states. However, you can keep 8-10 glofish tetras, 10-12 glofish danios, 5-6 glofish barbs, and 4-6 female glofish bettas in a 20-gallon tank. 

How Many Glofish In A 29-Gallon Tank?

A 29-gallon tank can house pretty much the same number of glofish as a 30-gallon would do. So, I would say you can keep 12-15 glofish tetras, 14-15 glofish tetras, 4-6 glofish bettas, and 9-10 glofish barbs in a 29-gallon tank. 

How Many Glofish In A 40-Gallon Tank?

You can keep plenty of glofish in a 40-gallon tank except glofish sharks that need 50 gallons minimum. You can house 18-20 glofish tetras, 12-13 glofish barbs, 20 glofish danios, and 8 female glofish bettas.

Final Words: How Many Glofish In A 30-Gallon Tank?

A 30-gallon tank is a great choice for first-time hobbyists. It’s easily manageable and offers a good extent of flexibility. 

However, it’s not suitable for all glofish species. Glofish sharks need around 50 gallons each as a bare minimum requirement, although the official website states that 20 gallons for a single shark will suffice. Unfortunately, this isn’t simply true. 

As for the rest of the glofish species, you can keep 12-15 tetras, 14-15 danios, 4-6 bettas, and 9-10 barbs in a 30-gallon tank. 

Recommended Readings!

What Do Baby Glofish Look Like? Photos And Videos!

Do Glofish Eat Each Other? Real Answers!

Are Glofish Aggressive? Why Are They Fighting?

Why Is My Glofish Swimming Sideways? 3 Reasons Why!

What Temperature Do Glofish Need? Do They Need A Heater?

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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.