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

Dec 27, 2021

How Big Do Glofish Get

Credits: Robert Kamalov (Creative Commons license)

Altogether, there are 5 different varieties of glofish – from tiny tetras well suited for small tanks to rainbow sharks that need 50 gallons each. So, how big do glofish get? What size tanks do they need?

I’ll answer all of your queries and some more. 

Buckle up! 

How Big Do Glofish Get?

Glofish can get anywhere between 2 to 6 inches long, depending on the species. Glofish tetras, danios, and bettas are small fish reaching only around 2-2.5 inches long. Glofish barbs get around 3 inches long, and glofish sharks can grow as big as 6 inches! 

How Big Do Glofish Tetras Get?

Glofish tetras are created by genetically modifying the beautiful black skirt tetras. So, they grow to the same size as their original cousins, which is 2-3 inches. 

How Big Do Glofish Danios Get?

Glofish danios were the first glofish fish to be ever created. These fish get as big as their original species, zebra danios, about 2 inches. Although small, these fish need a big tank owing to their hyperactiveness. 

How Big Do Glofish Bettas Get?

Glofish are just like regular bettas, except for their bright disposition. So, these fish get around 2.25 to 2.5 inches long. These are extremely hardy fish well suited for beginners and experienced hobbyists alike. 

How Big Do Glofish Barbs Get?

Glofish barbs are the genetically modified variants of the popular tiger barbs. In the aquarium, they can get around 3 inches long. Although they don’t get too big, they need ample space to swim due to their semi-aggressive nature. 

How Big Do Glofish Sharks Get?

Glofish sharks are genetically modified rainbow sharks. Therefore, they get around 6 inches long in captivity. Owing to their big size and angry disposition, these fish need big tanks. 

Now that the main query is out of the way, let’s answer some other important questions. 

Recommended Readings!

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

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!

What’s The Minimum Recommended Tank Size For Glofish?

Glofish Species Minimum Tank Size 
Glofish Tetras15 gallons 
Glofish Danios 10 gallons
Glofish Bettas5 gallons
Glofish Barbs20 gallons
Glofish Sharks 50 gallons

What’s The Minimum Recommended Tank Size For Glofish Tetras?

The minimum recommended tank size for glofish tetras is 15 gallons. These fish are small and can technically be kept in aquariums smaller than 15 gallons. 

However, the catch is that these are schooling fish and should ideally be kept in a group of 6 or more. And a 15-gallon tank would be a bare minimum requirement for that. 

If you keep them in a small tank, it will only add to their stress. As a result, they will lash out at each other and even resort to nipping fins. And that’s not a pretty sight at all. 

What’s The Minimum Recommended Tank Size For Glofish Danios?

The minimum recommended tank size for glofish is 10 gallons. However, these fish are super active and are known to dart around the tank like a flash. 

Therefore, I’d recommend getting a 20-gallon long tank or even bigger. 

Like neon tetras, glofish danios are schooling fish. You should at least keep 5-6 of them together, so they feel comfortable. 

From what I read on a forum, these fish prefer odd-numbered groups. 

So, 11-13 would be perfect in a 20-gallon long tank. 

What’s The Minimum Recommended Tank Size For Glofish Bettas?

The opinion on the ideal tank size for bettas is divided. Some say 2.5 gallons would suffice, while others claim they at least need 5 gallons each to live happily. 

I agree with the second school of thought here. A betta should at least be provided with 5 gallons each so they can lead a comfortable life. 

Also, it’s a super bad idea to add more than one male in small tanks without adequate space and hiding spots. They will literally fight to the death. 

So, if you plan to keep small tanks, I suggest raising only females. Give those majestic fins a miss. 

What’s The Minimum Recommended Tank Size For Glofish Barbs?

Don’t go by a glofish barb’s size. They pack a lot of feistiness for fish that barely grow over 3 inches long. Therefore, the bare minimum recommended tank size for these fish is 20 gallons. 

However, many seasoned aquarists recommend keeping them in at least a 30-gallon tank. There are a couple of reasons behind this. 

First, glofish barbs are highly active swimmers that need plenty of open space to swim. Second, these fish are tiger barbs at the end of the day. Therefore, they will become aggressive and resort to violence if there’s not enough territory. 

And lastly, tiger barbs are schooling fish. They should at least be kept in a group of 5-6. And as you can guess, a 5 or 10-gallon tank simply can’t house that many barbs. 

What’s The Minimum Recommended Tank Size For Glofish Sharks? 

Glofish sharks are just as active and aggressive as their ‘all-natural’ cousins. Hence, the minimum recommended tank size for keeping just one glofish shark is 50 gallons. Yes, you read that right! 

And if you want to raise more than one of these fish, be ready to get a tank that has a capacity of 125 gallons or upwards.

In small tanks, these active fish get stressed quickly and become pretty aggressive. 

Now, let’s see what the average lifespan of these fish looks like. 

How Long Do Glofish Live?

Here’s a table showing the average lifespan for different glofish species:

SpeciesLifespan
Glofish Tetras3-5 Years
Glofish Danios4-5 Years
Glofish Bettas3-5 Years
Glofish Barbs5-7 Years
Glofish Sharks 6-8 Years 

Now, let’s quickly skim through the required temperature and pH levels. 

What’s The Best Temperature For Glofish?

The best temperature for different glofish species looks like this:

SpeciesTemperature 
Glofish Tetras70°-80°F
Glofish Danios65°-77°F
Glofish Bettas78°-80°F
Glofish Barbs74°-80°F
Glofish Sharks 75°-81°F

What’s The Best pH Levels For Glofish?

The ideal pH range for different glofish species looks like this:

SpeciespH 
Glofish Tetras6.5-7.5
Glofish Danios6.5-7.2
Glofish Bettas6.5-7.5
Glofish Barbs6-7
Glofish Sharks 6.5-7.5

Frequently Asked Questions 

What Colors Do Glofish Come In?

Glofish currently come in six stunning colors:

  • Galactic purple 
  • Electric green 
  • Cosmic blue 
  • Starfire Red 
  • Sunburst Orange 
  • Moonrise Pink 

Are Glofish Injected With Dye?

No, glofish aren’t injected with dye. The beautiful fluorescent colors they sport are produced by an inherited fluorescent protein gene passed down from generation to generation. 

And those fluorescent protein genes were derived from the naturally occurring genes found in marine creatures like jellyfish. 

Are Glofish Hard To Keep Alive?

No, glofish aren’t hard to keep alive because the scientists who created them have deliberately chosen the hardiest, beginner-friendly species like bettas and barbs to make glofish. 

As long as you provide a stress-free, clean environment and feed healthy food at the correct interval, your glofish will live just as long as their non-modified cousins. 

That being said, sometimes, when you buy glofish, they can die on arrival owing to stress and travel fatigue. Therefore, always make a point to observe the fish first before buying it. 

Choose glofish that are active and swimming well, have rounded bellies, and don’t show any signs of anomaly like white spots, ripped fins, or strange swimming patterns. 

Final Words: How Big Do Glofish Get?

There are five different species of glofish. While some get just 2 inches long, some grow as long as 6 inches and require 50 gallons each. 

Glofish danios, bettas, and tetras are the smaller species – growing only about 2 to 2.5 inches long. Glofish barbs are slightly larger – getting around 3 inches long. And lastly, glofish sharks are the biggest in the lot, reaching up to 6 inches long! 

Recommended Readings!

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

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

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

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.