Can Glofish Live With Goldfish? It Can Be Costly!

Jan 27, 2022

Can Glofish Live With Goldfish

No chewing the fat this time. Let’s get straight to the facts. Can glofish live with goldfish? No, they can’t. I can give you at least half a dozen different reasons they shouldn’t be housed together.

I know, glofish and goldfish together would make a beautiful sight. 

But frankly, it gives me heebie-jeebies when hobbyists talk about doing certain things with fish that might potentially kill them just because it would look cool. 

Let’s get into the details now. 

Can Glofish Live With Goldfish?

First, all 5 glofish species are tropical species that require warm waters, while goldfish are coldwater fish. Second, smaller glofish like tetras, danios, and barbs will nip at your goldfish’s fins, whereas bigger, solitary glofish specimens like bettas and sharks will relentlessly bully your goldfish to the brink of death. 

So, I guess it wouldn’t be wrong to say glofish and goldfish together is a ‘match made in hell.’

Now, let’s look at these reasons and some more in depth below. 

Glofish And Goldfish Need Different Temperatures.

As I said above, all 5 glofish species were made by genetically modifying tropical fish. Therefore, they prefer their water on the warmer side. 

The temperature requirements for different glofish species look like this:

  • Glofish Barbs 74-80 degrees F (23-26 degrees C)
  • Glofish Tetras 70-80 degrees F (21-26 degrees C)
  • Glofish Danios 65-77 degrees F (18-25 degrees C)
  • Glofish Bettas 78-80 degrees F (25-26 degrees C)
  • Glofish Sharks 75-81 degrees F (23-27 degrees C)

On the other hand, goldfish are coldwater fish originally coming from freshwater bodies of East Asia. 

The ideal water temperature for goldfish would be 67-72 degrees F (19-22 degrees C)

Now, as you can see, the temperature requirements for glofish and goldfish barely overlap. I know the temperature needs for glofish danios and goldfish coincide with a very slim margin. 

But it is never a good idea to expose any fish to extremities for a prolonged period. 

I’ll now dish out a few tidbits on the consequences of keeping glofish and goldfish at the wrong temperatures. 

What Happens If Water Is Too Hot For Your Goldfish?

If the water temperature is too high, it will dramatically increase your goldfish’s metabolism. As a result, the fish will become more energetic and hyperactive than ever. 

And naturally, they need a generous oxygen supplement to keep up with their newfound zeal.

But there’s one small hiccup – warm water holds considerably less oxygen than cold water. So in more severe cases, there won’t be enough oxygen to go around, and as a result, your goldfish will suffocate. 

Once the oxygen level depletes, the fish will become weak and sluggish. So first, it will move to the bottom of the tank, where colder water holds relatively more oxygen. But this trick won’t last for too long as well. 

Eventually, your goldfish will begin to suffocate. And if you don’t intervene at the right time, you will end up with a dead fish. 

And to make matters worse, beneficial bacteria that reside in tanks need oxygen to break down ammonia into harmless compounds. 

And with a lack of enough oxygen in the tank, ammonia levels will naturally spike. 

As a result, it will burn your fish’s gills, dull its color, mess with its appetite, make it lethargic, and suppress your appetite. 

Needless to say, warm water can kickstart a host of potentially fatal problems for your goldfish. 

What Happens If The Water Is Too Cold For Glofish?

All 5 glofish specimens come from tropical waters. Therefore, they thrive in warmer temperatures. If the water gets too cold for their liking, it will slow down their metabolism. 

And when their metabolism is compromised, it will negatively impact their activity levels, reduce appetite, and severely stress them out. 

And when stressed, a fish’s body becomes incapable of properly producing white blood cells that strengthen its immunity. 

As a result, the fish’s immunity is compromised – making it susceptible to a wide range of diseases and infections. 

It’s been reported that good bacteria function to break down ammonia at 65 degrees F (18 degrees C). 

So, if the tank’s temperature is any lower than that, once again, the tank will experience a spike in ammonia levels. 

And you know the drill – the fish will experience painful signs like reddened gills, labored breathing, lowered appetite, and reduced metabolism. 

In a nutshell, keeping glofish in cool temperatures is similar to how you can survive without clothes in winter. You won’t die instantly, but you’ll soon catch flu, pneumonia, hypothermia and die. 

Fish are ectothermic beings. They rely on external temperature to regulate their body temperature. Therefore, it’s critical to maintain the right temperature for them at all times. 

Exposure to wrong environmental parameters for even a short period can lead to grave consequences no matter how ‘hardy’ your fish is. 

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Glofish And Goldfish Don’t Get Along

Glofish barbs, danios, and tetras are ill-famed for their fin-nipping habit, and rightly so. It’s never a good idea to keep these fish with slow-moving, long-finned fish like goldfish. 

These fish will undoubtedly gang up against your docile goldfish and take turns nipping its fins.

And this won’t just immensely stress out your glofish but also potentially lead to fatal infections and injuries if you don’t settle the matter in time. 

But remember, goldfish are no saints either. So when the opportunity strikes, it won’t think twice before gobbling your tiny glofish tetras or danios whole.

Now, when it comes to glofish bettas and sharks, they’d rather have the entire tank to themselves. They don’t believe in communal living. 

If you keep a docile goldfish alongside any of these two, there’s no doubt the goldfish will get bullied relentlessly. 

Both glofish betta and shark will push and chase it around, nip at its fins, and profusely stress it out to the point of death – and no, I’m not exaggerating. 

Glofish And Goldfish Have Different Dietary Requirements 

Glofish bettas, like the regular bettas, are carnivores. On the other hand, goldfish are omnivores inclined towards a plant-based diet. 

Therefore, you will need to provide different kinds of food for different fish each time – and frankly, it’s going to be a hassle. 

If you fail to fulfill their respective dietary requirements, the fish will become malnourished, its growth will be stunted, 

Likewise, glofish danios, barbs, and tetras are omnivores with a strong preference for an insectivorous diet. But, once again, their dietary needs don’t align with that of a goldfish. 

And you already know what happens when the fish eats the wrong kind of food or is malnourished. 

Lastly, and surprisingly, glofish sharks and goldfish have somewhat similar food requirements. They both thrive on algae, plant-based food, and occasional live food. 

However, since glofish sharks are incredibly possessive about the resources, chances are that your goldfish may not be able to eat as much as it wants to or needs to. 

This can lead to starvation and consequent health hazards. 

Also, goldfish need to consume more fibrous food to prevent constipation, which they’re very susceptible to. 

Goldfish often incur digestion problems since they don’t really have ‘true’ stomachs. So, feeding food meant for tropical fish, which is hard to digest for goldfish, only means you’re throwing them under the bus.

Goldfish Will Make The Tank Inhospitable For Your Glofish 

It wouldn’t be wrong to say goldfish are the turtles of the fish world. They produce an unbelievable amount of waste every day. They will constantly keep you on your toes when maintaining the water parameters. 

Since goldfish produce a sizeable amount of waste, they have evolved over hundreds of years to live in a subpar environment to some extent. 

However, don’t make this an excuse to skip water changes or skimp while getting a filtration mechanism. 

On the other hand, most glofish species produce significantly less bioload than glofish.

Therefore, they can tolerate poor living conditions as much as a goldfish would. 

And since most glofish don’t require as much space as goldfish do and are kept in smaller enclosures, their tanks have relatively weaker filtration systems that can’t cope with the high levels of waste goldfish produce. 

And before you know, the tank’s ammonia and nitrite levels will go off the roof and invite serious problems – like death. 

You Will Need A Super Big Tank To Begin With 

The biggest fish in the glofish family are glofish sharks that grow around 6 inches long. On the flip side, most fancy glofish varieties grow about 7 inches long. 

Moreover, many common and comet goldfish species grow to a foot long and even more. 

So, they need a super big tank. 

Now, imagine keeping them with glofish sharks that require 50 gallons each at a bare minimum. 

You will need a gigantic tank, to say the least. And while big tanks are always better than small ones, it’s not always practical for everyone to keep and maintain a big tank – both in terms of investment and space. 

And it’s not just glofish sharks that aren’t compatible with goldfish when it comes to spatial needs. 

For instance, glofish bettas are super territorial fish. They’re even known to headbutt their own reflections. 

So, if you were to keep them together with goldfish, you’d once again need a huge tank. 

And lastly, glofish danios, barbs, and tetras are schooling fish. If you were to keep only a few of them, you could get away with keeping them in a mid-sized tank with goldfish. 

However, schooling fish need to be kept at least in groups of 6. Therefore, adding at least 6 of these fish alongside goldfish would require a huge tank.

And big tanks come with big responsibilities.

Your Goldfish Can Eat Your Glofish 

Goldfish aren’t predators. They aren’t known to be very aggressive too. So, they will seldom hunt down smaller fish and consume them. 

However, goldfish are ravenous eaters. They won’t even think twice before devouring every morsel of anything remotely edible. 

So, it’s not uncommon for them to swallow small fish mistaking them for food. 

In most cases this happens, it’s not done aggressively and is purely accidental. 

Therefore, tiny glofish like danios and tetras are definitely in danger in the company of goldfish. 

Glofish And Goldfish Have Different Disease Tolerance 

Scientists believe there are at least 33,000 different fish species in the world. And tropical species like glofish barbs and bettas are entirely different from coldwater species like goldfish. 

Different diseases affect them differently, and they have distinct disease tolerance levels. 

There’s a good chance that your goldfish will get sick from a disease that won’t necessarily impact your glofish – and vice versa, of course! 

For instance, coldwater species like glofish are more susceptible to invasive diseases than tropical fish. 

Goldfish will also get ill more readily in warmer temperatures than in cooler temperatures. 

And the opposite can be said about glofish that need warmer temperatures, right?

I think I have got my point across. Now, let’s look at what real hobbyists have to say on this matter. 

I collected some real answers on “Can glofish live with goldfish?” – and here’s what they have to say! 

Can Glofish Live With Goldfish? Real Answers! 

Note: The answers and opinions listed below purely belong to the respective authors.

“They really shouldn’t be housed together. Goldfish prefer relatively cool temperatures, whereas glofish are tropical fish that prefer much warmer temperatures.”

“Your goldfish won’t die upright if kept in warmer water, but it’s far than ideal. It will make them prone to illnesses and shorten their lifespan.” 

“Goldies are coldwater fish, and glofish are definitely tropical. So there might be some overlap in their tolerance levels, but my gut feeling says they wouldn’t thrive.”

“Goldfish and glofish danios don’t make a good combo. But, depending on their sizes, danios can become a snack any day.”

“My girlfriend started out with 5 glofish and 3 fancy goldfish in a 55-gallon tank. The goldies ate 4 glofish. A year on, 1 glo light is still cruising.”

Frequently Asked Questions

Here are a few frequently asked questions on glofish and goldfish. Have a look! 

Credit: Ho-Wen Chen (CC License)

Can Goldfish Eat Glofish Food?

Yes, goldfish can eat glofish food, but it isn’t really ideal for them. Goldfish need to consume fibrous food like plants and veggies to prevent constipation, to which they’re very susceptible. 

As goldfish don’t have a ‘true’ stomach, they often run into digestive problems. And feeding food meant for tropical fish will only put them at a higher risk of constipation. 

Can Glofish Live With African Cichlids?

No, it’s not a good idea to keep glofish with African cichlids. First, most African cichlids are incredibly aggressive and territorial fish. 

Therefore, if you keep glofish sharks and bettas with African cichlids, the tension and agitation in the tank will be so high that we can’t rule out duels and potential death. 

And oh, African cichlids can very well injure and eat your glofish tetras, barbs, and danios.

Can Glofish Live Alone?

Glofish sharks and bettas can live alone. In fact, they would love to have the entire tank to themselves. They despise socialization and small talks – just like me! 

On the other hand, glofish danios, tetras, and barbs are schooling/shoaling fish. If kept alone, they will become lonely, stressed, sad, and irritable. All in all, they will lead impoverished lives. 

Therefore, they should at least be kept in groups of 6. 

Final Words: Can Glofish Live With Goldfish?

No, sorry! Glofish and goldfish cannot cohabitate together. Glofish are tropical fish, and goldfish are coldwater fish. Thus, they require different water temperatures to live comfortably. 

Second, their diets are also quite different from each other. While almost all glofish species are insectivores, goldfish prefer a plant-based diet. 

And lastly, glofish tetras, danios, and barbs have a knack for nipping fins. Therefore, they shouldn’t really be placed with goldfish that boast beautiful, long, and flowy fins.

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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.