Can Guppies and Glofish Live Together?

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As a novice aquarium enthusiast, you may have heard about guppies, but you probably haven’t heard of Glofish. A quick search will inform you that these are basically fish that glow in the dark thanks to their neon-like properties.

But there’s much more to these fish than that, so let’s discuss them before assessing their relationship with guppies.

Glofish aren’t a species of fish but a characteristic. Several fish species fall into the category of Glofish, including zebra danios, black skirt tetras, tiger barbs, rainbow shark, and betta fish.

These fish glow in various colors in the dark, and they are the result of biological engineering, as scientists mixed a jellyfish’s green fluorescent protein into the fish’s DNA to obtain fluorescent fish.

The first species to undergo this treatment was the zebra danios, and the purpose of the procedure wasn’t esthetical at first.

The purpose was to create a fish species that would glow when in the presence of specific environmental toxins and chemicals. This was meant to help researchers identify areas with heavy pollution so they could address the issue faster and more effectively.

The result was a neon-glowing fish species that people loved. The fish’s uniqueness and appeal to the public led to other species receiving similar treatment, like the ones I’ve already mentioned. As a plus, the color diversity also improved dramatically over time.

You can now find various species of Glofish in colors like:

  • Sunburst Orange
  • Electric Green
  • Moonrise Pink
  • Cosmic Blue
  • Galactic Purple
  • Starfire Red

You even have a rainbow shark that can display several colors on its head and fins if you fancy that.

But the interesting question is – are these fish injected with color? The answer is no. Their coloring stems from genetic makeup. It is completely natural, it passes on from parents to offspring, and it doesn’t affect the fish’s quality one bit.

But how do Glofish fare when placed in the same environment with guppies? Can they cohabitate in the same tank or not? Let’s see where the truth lies.

Do Glofish Get Along with Guppies?

Yes, but not all of them. The question is a bit loaded since it presumes that Glofish are a different fish species. And they’re not, they’re actually several different species. So, we can only answer the question by assessing each species’ compatibility factor in relation to guppies.

So, let’s do that right now:

  • Betta Glofish – Bettas are typically territorial and will display aggressive behavior towards other fish, especially calmer and more timid ones. You know, like guppies. Betta males, in particular, tend to be more violent by nature, especially one towards the other. Bettas can get along with guppies, but your involvement will be especially higher, as you will need to monitor the tank dynamics around the clock. I wouldn’t recommend it.
  • Tiger Barb Glofish – The tiger barb is another medium-sized fish, reaching sizes of up to 3 inches. This makes it slightly larger than guppies, practically double the size of an average male guppy. But that’s not necessarily the problem here. The real problem is the tiger barb’s personality and behavior towards other fish species. Tiger barbs can be quite the bullies, especially against docile and calm fish species like guppies. They also prefer large-finned fish as harassment targets, and guppies also qualify for that. It’s never a good idea to pair the 2 species.
  • Rainbow Shark – As beautiful as these fish are, they make for terrible tank mates for guppies. These fish will grow around 6 inches in length, even larger by some accounts, and typically display a territorial and aggressive demeanor towards other fish. Rainbow sharks will bully and even kill more peaceful fish populating their territory, especially smaller ones like guppies. If there’s a fish species that you should avoid pairing with guppies, it would be this one.
  • Zebra danios Glofish – These small fish seem like a good fit as tank mates for guppies. They only grow to be around 2 inches in size, and they also like to live in shoals, like guppies. They are omnivorous, peaceful, but rather energetic and will tolerate other species, making them ideal for community tanks. The problem is that zebra danios are cold-water fish and prefer temperatures around 60 to 74 F. Guppies, on the other hand, are warm-water fish, thriving in temperatures around 72 to 82 F. This means that the 2 aren’t really compatible.
  • Black Skirt Tetras Glofish – Tetras grow up to 3 inches max, are omnivorous, peaceful, and work well in community tanks. They will get along with any other peaceful fish species, guppies included. If you want a type of Glofish for your guppy tank, this is pretty much the only species you should get. At least until the emergence of other Glofish species.

Keeping Glofish with Guppies

As you can see, when talking about Glofish, in this context, we’re actually talking about tetras since this is the only one that qualifies for living with guppies. So, let’s see what different requirements to consider when pairing the 2:

Tank Size

The tank’s size is important since it defines the fish’s quality of life over time. It doesn’t matter that the water quality is pristine if the fish bump into each other constantly.

Such an environment is enough to throw off even the calmest fish species, and guppies are some of the top contenders for that award.

As a general rule, provide each guppy with at least 2 gallons of water, and you can use the same rule for tetras.

When it comes to pairing the 2 together, the tank’s size depends on the number of fish you have. Seeing that guppies and tetras prefer to live in groups of at least 6 individuals, a 25-30-gallon tank for both groups should suffice.

This is enough room to also add some plants and decorations designed to give the aquarium a more natural vibe, making the fish feel more comfortable and at ease.

Water Temperature

Fortunately, both guppies and tetras tolerate the same temperature range, around 72 to 82 °F (85 °F for tetras.) This temperature range is sufficient to keep the 2 species healthy and active in the long run.

If you can achieve and maintain this temperature without a heater, do so. If not, a heater is a must since guppies, especially, have a low tolerance for fluctuating water parameters.

They can handle some temperature shifts occasionally, but not too large and certainly not too frequent.

The same applies to tetras, which also prefer stable water conditions and temperature.

Diet and Feeding

Both guppies and tetras are omnivorous, so they will consume the same type of food. The key aspect here is diversity.

Provide your fish with a diverse diet, including plants and animal-sourced protein, and they will remain healthy, satisfied, and thriving over the years.

A well-balanced diet is necessary to both nourish the fish and boost their reproductive rates if that’s something that concerns you. Not like it matters anyway since guppies and tetras will breed as much and as often as they can.

Water Changes

The need for water changes increases proportionally with the number of fish you have. The more of them live in the same enclosed space, the more and the faster the water’s quality will decrease.

Having a lot of fish will result in a lot of fish waste and food residues accumulating on the substrate, soon becoming an environmental hazard.

Depending on your fish’s needs, you can mitigate the problem by performing regular water changes. As a rule, I suggest weekly water changes, changing no more than 10-15% of the water.

This is enough to eliminate excess ammonia and improve the water’s oxygenation without disturbing beneficial bacteria cultures or diluting water minerals too much.

Number of Fish

The number of fish to keep depends solely on the tank’s size. Otherwise, there is no magic number to adhere to. As a general rule, the more fish you have, the higher the maintenance requirements.

You will need to perform more regular water changes, clean the substrate more often, and watch for signs of aggression between the fish.

So, as a novice in the fish-keeping business, you might want to start with 5-6 fish of each species for your first community tank.

You can then breed them, care for the fry, and learn how to maintain an even larger fish population.


Guppies and tetras can easily get along with each other, as they are similar in environmental requirements, food preferences, and overall behavior. Unfortunately, I can’t say the same about the other species of Glofish.

If you absolutely must have a type of Glofish in your guppy tank, stick to tetras. If you’d prefer other species as well, keep them in a separate tank since they don’t mix well with guppies.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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