Glofish tetras were launched around 2013. The same company behind glofish danios, Yorktown Technologies, are their creators. And ever since their first launch, glofish tetras have steeply risen to popularity and made their way into the homes of million Americans.
Glofish tetras are among my favorite glofish species for a couple of reasons.
First, their interesting shape and colors quickly set them apart from other fish in the tank.
Second, they’re literally a piece of cake to take care of. It makes them an approachable and manageable option for aquarists of all skill levels.
In this one-stop guide, I will tell you all there’s to know about caring for glofish tetras.
I will cover habitat requirements, water parameters, breeding, tankmates, and so much more.
So, tune in!
Glofish Tetra Quick Introduction
| Name | Glofish Tetra |
| Original Species | Black Skirt Tetra |
| Scientific Name | Gymnocorymbus ternetzi |
| Care Level | Easy |
| Breeding | Egg layers |
| Temperament | Peaceful and social |
| Diet | Omnivores |
| Minimum Tank Size | 15 gallons |
| Temperature | 68-79 degrees F (20-26 degrees C) |
| pH | 5.8-8.5 |
| Hardness | up to 15 dGH |
| Tank Level | Mid dweller |
There are two glofish tetras variants – standard and long-finned variants.
However, both varieties were made by genetically modifying black skirt tetras that originally come from Paraguay and Guapore Basins in South America, where they inhabit slow-moving creeks and upper layers of the water.
And as you already know, glofish tetras were made by genetically modifying the eggs of regular black skirt tetras. Fluorescent protein genes were injected into black skirt tetras’ embryos, which led them to have a luminous appearance.
The genes used were extracted from jellyfish and other marine organisms.
Note that only the first generations of glofish tetras were injected with the fluorescent gene.
The glofish tetras that we see at pet stores today got their colorful disposition from their parents – the fluorescent protein gene is passed down from generation to generation.
Glofish Tetra Lifespan
Glofish tetras live for around 3-5 years in captivity. But with proper upbringing, they are even known to make it past their 7th birthday!
The environment you create, the diet you feed, and the tankmates you choose for it from day 1 play pivotal roles in determining how long your glofish tetra will live.
Glofish Tetra Appearance
Glofish tetras are deep-bodied, laterally compressed species.
The fish is set apart by its two vertical stripes and what appear to be overly developed anal and dorsal fins that make it looks as if it has a skirt, with most of the fish’s mass on the bottom half of the body. And that’s how the fish got its moniker.
Glofish Tetra Colors
Glofish tetras come in 6 stunning and probably patented colors: electric green, cosmic blue, starfire red, sunburst orange, moonrise pink, and galactic purple.
My favorite is moonrise pink. That pop of pink coupled with an iridescent glow makes the tetras look nothing short of magical.
And by the way, glofish tetras are born with these brilliant colors. They’re in no way painted, injected, or dyed like some jellybean cichlids painted glassfish are.
Glofish tetras inherit their beautiful, harmless, and lifelong color from their parents.
And while we’re at it, let’s make one thing clear.
Glofish tetras don’t exactly glow from inside. Instead, they absorb the light and then re-emit it. Therefore, the fluorescent colors appear more vibrant and brighter as the amount of light increases.
Blue LED lights are the most flattering to bring out their best colors.
Glofish Tetra Size
The reguar glofish tetras grow around 2 inches (5 cm) long, and long-finned glofish tetras can get about 2 ¼ inches (5.5cm) long.
However, both types of tetras can start breeding by the time they’re 1.5 inches long.
These fish take about a year or so to reach their maximum potential size.
Male VS Female Sexual Differences
Since both males and females inherit the fluorescent protein gene, there’s no way you can tell them apart by just observing their color.
Notice the dorsal fin. A male’s dorsal fin is slimmer and more pointed than a female’s.
Likewise, a male’s frontal part of the ‘skirt’ or anal fin is quite noticeably broader than the females. Usually, a female’s ‘skirt’ runs parallel to the stomach line.
A mature female also has a more plump, rounded appearance – especially if she is gravid.
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Glofish Tetra Temperament
Glofish tetras are pleasant, friendly, and peaceful fish. Since they are schooling fish by nature, they should at least be kept in groups of 6 or more. And owing to their calm demeanor, they make excellent community fish.
Glofish tetras, like their non-modified cousins, seldom display any signs of aggression. The only time you need to be careful with these fish is when they’re kept with long-finned fish.
Slow-moving, long-finned fish like bettas and angelfish don’t make good tankmates for glofish tetras because the latter has a knack for nipping fins. Besides this one hiccup, there’s not much you need to worry about.
When kept in large groups, they will keep to themselves and not torment any smaller fish.
Glofish tetras are incredibly active when young. However, they become more sedentary as they grow old.
And as far as a daily routine is concerned, these fish spend a good chunk of their day swimming around, exploring nooks and crannies, and playfully chasing around each other.
Although they’re schooling species, they don’t really school a lot in captivity. They’re neither in danger nor have to forage for food – thus, you may not always see them schooling. But when they do, it’s definitely a beautiful sight to behold.
Glofish Tetra Tankmates
Since glofish tetras are schooling fish, the best tankmates for them would be other fish from their own family. Also, you should avoid keeping them together with long-finned fish like fancy guppies and goldfish, bettas, and angelfish.
Some ideal tankmates for glofish tetras include:
- Chili Rasboras
- Celestial pearl danios
- Cardinal tetras
- Neon tetras
- Dwarf gouramis
- Bolivian Rams
- Kuhli loaches
- Cory Catfish
- Plecos
- Hatchet fish
- Harlequin Rasboras
- Rubber Lipped Plecos
- Lemon tetras
- Black skirt tetras
- Platies
- Mollies
- Otocinclus catfish
And here’s a shortlist of tankmates you should avoid for your glofish tetras:
- Tiger barbs
- Oscar fish
- Rainbow sharks
- Red-tailed sharks
- Flowerhorn
- Bucktooth tetra
- Wolf cichlid
Truth be told, instead of finding the ‘ideal’ tank mates for your glofish tetras, you should aim to keep more than 6 glofish tetras in the same tank. That’s because these fish really enjoy their own company.
If you keep them in smaller numbers, it will only make them stressed and agitated.
They will then show their mean side – chasing and nipping weaker tankmates.
Glofish Tetra Diet
Glofish tetra’s forebears, black skirt tetras, are omnivores that primarily snack on worms, small crustaceans, and insects in the wild.
So, your glofish tetras will also appreciate an entomophagous diet. However, they are omnivores and will accept a wide variety of food in the tank. They aren’t picky at all about what they eat.
The general practice is to zero in on 2 or 3 types of quality pellets or flake foods for staple diet and fortify the diet with the occasional inclusion of live or frozen food.
Here’s a list of food you can give your glofish tetras:
- Pellets
- Flakes
- Brine shrimp
- Daphnia
- Frozen bloodworms
- Frozen blackworms
- Tubifex
- Spirulina
- Blanched veggies like broccoli and zucchini
- Insect larvae
- Crickets
As for feeding frequency and quantity, you can give them 2 meals every day – an amount they can finish within 3 minutes or so.
If you constantly find leftover food in the tank after the feeding session, it means that you’re overfeeding the fish. So cut down on the portion you give.
Overfeeding won’t just make your fish obese and unhealthy but also pollute the water – leading the way for a host of parasites and pathogens waiting to strike.
If you’re interested, here’s a link to Glofish Special Flake Food by the brand Glofish itself.
Apparently, it’s made with a proprietary formula that maximizes the fish’s brightness.
I don’t know how true that is, but it does contain some nice ingredients like ground brown rice, dried yeast, shrimp meal, and fish oil.
And here’s a link to freeze-dried bloodworms that you can treat your tetras with once in a while:
Water Parameters For Glofish Tetras
Here’s what ideal water parameters look like for glofish tetras:
- Temperature: 68-79 degrees F (20-26 degrees C)
- Breeding Temperature: 82 degrees F (27.8 degrees C)
- pH: 5.8-8.5
- General Hardness: Up to 18 dGH
- Ammonia: 0 PPM
- Nitrate: 0 PPM
- Nitrite: Below 20 PPM
- Water Movement: Moderate
As you already know, maintaining the correct water parameters is paramount when it comes to keeping your glofish tetras healthy.
Interestingly, the scientists who created glofish deliberately chose hardy species like tetras so they don’t become prone to complications that may arise from genetic modifications.
Therefore, glofish tetras can reasonably tolerate a wide range of fluctuations in their environment. But let’s not make that an excuse for keeping these fish in subpar environments.
After all, any fish will become susceptible to diseases when consistently exposed to the wrong environment.
The rule of thumb for any given fish is to emulate the water conditions of their natural habitat. But since glofish tetras aren’t found in the wild, let’s look into the natural habitat of their wild cousins, black skirt tetras.
Black skirt tetras come from South American water bodies that are slightly warm and acidic. Therefore, you should strive to echo similar parameters in your glofish tetra’s tanks.
Although glofish tetras are not at all demanding about water conditions, they do prefer soft, acidic, and slightly tannin-stained water.
Initially, the water you keep them in should closely match the water they were kept in at the suppliers. No matter how hardy glofish tetras are, they absolutely despise sudden changes to their environment.
If you’re serious about raising glofish tetras, investing in a solid filtration system is a must. There’s no alternative to this.
Although tetras don’t really produce a ton of waste individually as goldfish do, a sizable school of fish can quickly pollute and alter the water quality.
Therefore, your filtration system should be equipped enough to keep ammonia and nitrite levels at 0 PPM and nitrate levels below 20 PPM.
Another indispensable thing you should invest in is a reliable water testing kit that should be used every week or so.
We use the fan-favorite API Freshwater Master Kit at Urban Fishkeeping and recommend you do so.
I recently learned that liquid-based tests offer more reliable and accurate readings than test strips.
Here’s a link to API’s liquid-based test kit if you are interested:
In order to improve the water quality, we recommend replacing 25 t0 50% water every week.
But this rule isn’t etched in stone. In the end, it all boils down to your stocking number and your filter’s capacity.
Below, I’ll share some things you should do daily to ensure the good health of the fish and its environment. Note that the list isn’t conclusive, but it does cover the most essential bits.
Have a look!
Things To Do Daily
- Count and observe the behavior of your glofish tetras
- Remove uneaten food
- Manually check all equipment
- Top off the water level
- Check the temperature
Things To Do Weekly
- Wipe down the tank’s outer surface
- Shake off debris from decorations and plants
- Scrape the inside surface of the glass
- Siphon substrate
- Perform a partial water change
- Test water parameters
Things To Do Monthly
- Prune plants as needed
- Thoroughly clean decors
- Perform all tasks listed in a weekly list
- Change the filter media
Minimum Recommended Tank Size For Glofish Tetras
15 gallons is the minimum recommended tank size for glofish tetras. But if possible, always go for a bigger tank.
I know tetras are often restricted to tanks as small as half-gallon. So, 15 gallons may seem like too much for small tetras.
But hear me out, I’ll give you my reasons why they at least need 15 gallons.
First, the smaller the tank, the more temperamental and dangerous it is. The water parameters will change quickly – and even worse, the change can be felt throughout the tank in no time.
Second, small tanks mean a quicker buildup of harmful compounds like ammonia and nitrate that can be downright fatal to your fish if you don’t intervene in time.
Third, small tanks are known to stunt a fish’s growth. That’s because fish don’t get enough exercise in a small tank. Also, fish are known to release growth-inhibiting pheromones into the tank that stunt the growth of the tank’s other inhabitants.
In small tanks, these pheromones don’t get diluted easily. Instead, they get absorbed into the fish’s body – stunting their growth.
Fourth, small tanks give rise to territorial disputes that severely stress out the fish. And when stressed, a fish’s system inhibits the production of white blood cells – directly resulting in lowered immunity.
I can go on and on about why and how small tanks are bad for fish. But I think these 4 reasons should be enough for now, right?
Substrate And Decor For Glofish Tetras
For substrate, I would recommend using dark sand. River gravel works fine too.
Since glofish tetras rarely spend any time at the tank’s base, this shouldn’t be of much concern.
That being said, darker colors quite accurately mimic the decaying leaves at the bottom of rivers black skirt tetras call home in the wild.
For decors, you can add caves and driftwoods. These will serve as great hideouts for the times your fish need to recharge their batteries. Driftwood will also help to keep the water acidic.
Plants also make great additions to your glofish tetra’s aquarium. These fish love tall and big plants that they can swim through and explore.
I recommend adding tall plants like amazon sword, hornwort, and java fern.
That’s because these fish typically swim in the middle region of the tank. And tall plants will ensure the fish has plenty of places to explore and hide around without having to drive down to the bottom of the tank.
But be mindful not to go overboard with the plants. Glofish tetras are active swimmers that need plenty of space to move around freely.
Recommended Equipment For Glofish Tetras
Since tetras don’t grow very big, beginners often keep them in small round tanks with no filter or heater. But as you can guess, proper filtration and heating system are
Instrumental in keeping your glofish tetras healthy and ensuring they live a long life.
Here’s a list of handpicked equipment for your glofish tetras. Don’t forget to check them out!
AquaClear 30 Power Fish Tank Filter
What we like about it:
- Lifetime warranty
- Quick and easy installation
- 3-step filtration
- Uses 3 types of media: biomax, foam, and activated foam
Fluval M50 Submersible Heater
What we like about it:
- Blends into the aquarium environment
- Computer-calibrated thermostat
- Slim profile
- Shock-resistant glass
Tetra Whisper Easy-To-Use Air Pump
What we like about it:
- Quiet operation
- Thousands of 5-star reviews
Breeding Glofish Tetras
Breeding glofish tetras is neither hard nor easy. But it is definitely illegal. Apparently, it’s against the law to ‘intentionally’ breed glofish tetras.
But if you have fish of both sexes present in the tank, they’re bound to yield some fry sooner or later. Just make sure that you don’t sell or barter them, so you don’t land in legal problems.
Glofish tetras, like their original counterparts, do not have the slightest parental instinct. They will gobble up the eggs at every chance they get. Therefore, saving the eggs from their own parents and raising them into adulthood can be difficult for beginners.
Below, I’ll dish out how to breed glofish tetras in different segments. Let’s start!
Preparing Fish To Breed
For the best success rate, females should be conditioned separately from the males at least 7 to 10 days before spawning. Feed both parties plenty of live food rich in protein.
Since adults eat the eggs and younglings, you need to prepare a separate breeding tank where you’ll raise the fry later. The tank shouldn’t be any bigger than 10 gallons. Otherwise, the fry will have a hard time finding food.
Likewise, use a sponge filter, so it doesn’t suck in eggs and fry.
In the breeding tank, use the same water as the main tank.
I’d also recommend using artificial grass, a net, or a spawning mop. These accessories will offer some protection for the eggs after the breeding process. Our aim here is to make it as difficult as possible for the adults to find the eggs.
Mating Ritual
Place the bonded pair into the main tank and continue feeding protein-rich live foods.
The female will become gravid in a few days, as you can see from her distended and swollen belly.
At this stage, the male will start chasing the female, which in the fish language is ‘courting.’ The male will start chasing the female through the plants and decors, occasionally quivering.
You have to keep a watchful eye on them at this period, so the male doesn’t excessively harass the female.
If the male is being too hostile, remove him from the tank.
Once the female is ready, she will lay hundreds of eggs over a period of 2-3 hours.
Like the rest of the fish from the glofish family, glofish tetras are egg scatterers. They will not lay eggs at one particular place. The eggs will be scattered all over the substrate, plants, and decors.
Most eggs will sink to the bottom. And this is why it’s a wise idea to have some sort of grass or mesh netting. The eggs will fall through it to the bottom, where they will be hidden from the adults.
Once the spawning session is complete, remove the parents, so they don’t commit infanticide.
Caring For The Fry
The eggs will hatch within the next 24 to 36 hours. Glofish eggs are neither colorful nor glow. If you want to read up more on glofish eggs, here’s a link to our in-depth article.
What Do Glofish Eggs Look Like? Photos And Videos!
The fry will rely on their yolk sac for the first few days for nutrition. Once they transition to the wiggler stage, you can give them baby brine shrimp, egg yolk paste, infusoria, microworms, and pulverized flake food.
When young, fry are highly susceptible to starvation. Therefore, you should feed them several times a day. And as I said above, the tank shouldn’t be too big. This will only make the food hunt more difficult.
In a couple of weeks from hatching, the fry will grow big enough to not be devoured by other fish.
Diseases In Glofish Tetras
No matter how hardy, like all freshwater fish, your glofish tetras are prone to certain health conditions like parasitic infections, skin flukes, ich, bacterial infections, and swim bladder disease.
Glofish tetras are extremely hardy species. So, if the tank’s conditions are maintained at all times, they’ll rarely contract any disease.
Due to their incredible resilience, in most cases, an outbreak of disease is often limited to just one or a few fishes if dealt with at an early stage.
Ich, a common aquarium disease, is caused by a parasitic infection that’s brought on by stress and poor water parameters. Your fish will develop tiny white lesions throughout its body.
If not dealt with in time, ich can prove fatal and wipe down the tank’s entire population.
We swear by this treatment by Hikari to treat ich. Here’s a link if you’re interested:
Prevention is always better than cure. Thus, be mindful about testing the water quality frequently and creating a stress-free environment to keep ich outbreaks at bay in the future.
Glofish tetras are also susceptible to bacterial and fungal infections. Some of them are dropsy, fish fungus, and fin rot. Most of these conditions can be avoided and treated by improving water parameters and using over-the-counter medications.
But always make sure to contact a vet before starting any new medication.
Final Words: Glofish Tetra Care Guide
There are several ethical questions surrounding the development and sales of glofish tetras. While some think it’s absolutely unnecessary and cruel to genetically modify fish for aesthetic purposes, others are endlessly fascinated by the science behind it.
Either way, if you have already brought home glofish tetras or are planning to, I hope this guide will be helpful and encourage you to make the right choices for your fish.
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