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Glowlight Tetra Care: Everything You Need To Know

Glowlight Tetra Care: Everything You Need To Know

Glowlight Tetras are vibrant little freshwater fish. They are colorful, active, and a lot of fun to watch in your aquarium. They have a peaceful demeanor and are a popular choice for beginners because they are easy to care for and a joy to watch.

Everything you need to know about Glowlight Tetras includes their preferred water temperature of 74°-82°F (23.3°-27.7°C), that they like slightly acidic pH, and that they like their water to be on the softer side. Recreating the tetras’ natural habitat as closely as possible will keep them happy.

In this article, we will explore every aspect of Glowlight Tetra care, from understanding their natural habitat to creating an ideal tank environment. We will also delve into their dietary requirements and offer insights into maintaining their overall health and well-being.

Glowlight Tetra Overview and Natural Habitat

  • Common name: Glowlight Tetra
  • Scientific name: Hemigrammus erythrozonus
  • Care level: Easy
  • Size: 1.5 inches (3.8 cm)
  • Lifespan: Two to four years
  • Temperament: Peaceful
  • Diet: Omnivores
  • Group size: At least six
  • Minimum tank size: 10 gallons
  • Tank level: Middle dweller
  • Water temperature: 74°-82°F (23.3°-27.7°C)
  • Water pH levels: 5.5 to 7.5
  • Water hardness: 6 to 15 dGH

The Glowlight Tetra is an excellent choice for beginners in raising fish. They’re easy to care for and don’t need much maintenance.

Glowlights originated in South America, in the Essequibo River in Guyana. The water is very dark due to its large amounts of plant matter. As the plants decay, the water becomes very soft and acidic.

The species became popular among aquarists in 1933 and are now bred in captivity instead of imported from their natural habitat.

These tetras are peaceful and make great tank mates for many fish. They’re sometimes confused with Glowlight Rasboras, but you can tell the difference by looking for the adipose fin only on the tetras.

Glowlight Tetra Appearance and Size

Like other tetras, the Glowlight Tetra has a torpedo-shaped body. They’re mostly a silver transparent color and feature a bright red or orange stripe that runs through the length of their entire body. Their fins are also mostly clear and have a red or orange blotch on the part of their dorsal fin.

These tetras also have very unique eyes. The colorful stripe also goes through their eyes;; the rest is silver, like their bodies.

The adults are tiny, usually only reaching 1.5 inches (3.8 cm) at their longest. This size makes them similar to Neon Tetras.

Difference Between Males and Females

The differences between male and female Glowlight Tetras are very slight. The females are rounder and a bit larger than the males. Since they have a larger stomach, the stripe through their middle is often curved.

Males are smaller, straighter, and usually have brighter colors, especially during their mating season.

The males are peaceful by nature but may show aggression if they aren’t in a large enough school. They may chase each other and pick on a few of the tetras. To prevent this, you’ll want to add more Glowlights and plants to your tank.

Glowlight Tetra Personality and Behavior

Glowlight Tetras are very calm, peaceful fish that live in shoals. So, you’ll need at least six of them in a tank, or they’ll become stressed. The more you can keep, the happier they’ll be.

These tetras love forming groups and exploring the decorations in their tank. Having a lot of plants and rocks for them to check out will keep them active and moving. They are a lot of fun to watch dart around the tank.

As a shoaling species, glowlight tetras regularly group up and dart around the tank to create an eye-catching display of color.

Glowlights are even more relaxed than other species of tetras and won’t nip at fish with long, flowing fins. This aspect makes them the best community tetras for tanks with multiple types of fish.

Glowlight Tetras are active during the day and sleep during the night. You might notice them huddled together near the bottom of their tanks when it’s dark.

Glowlight Tetra Expected Lifespan

With excellent care, Glowlight Tetras typically have an average lifespan of two to four years, but under optimal conditions, they can live even longer, extending their lifespan by a few additional years.

To help Glowlight Tetras achieve their maximum potential lifespan, it is essential to provide them with a nutritious diet, pristine water, and ample hiding places. These tetras are highly susceptible to the negative effects of improper diets and contaminated water, so it is crucial to prioritize their care and well-being to ensure their longevity.

Glowlight Tetra Care and Tank Set Up

Glowlights are easy to care for and a good option for first-time fishkeepers. You can tell that you’re doing well if your tetras are vibrant and active.

Your fish will thrive if you can follow these care and tank setup guidelines:

Tank Size

When considering the ideal tank size for Glowlight Tetras, it is important to provide them with an environment that promotes their well-being and allows for their natural behaviors. While Glowlight Tetras are small in size, the appropriate tank size plays a crucial role in their overall health and happiness.

A minimum tank size of 10 gallons is recommended for housing a small school of Glowlight Tetras. This size can comfortably accommodate up to six tetras, providing them with adequate swimming space and room to establish a social hierarchy. However, keep in mind that maintaining water quality becomes more challenging in smaller tanks, requiring more frequent monitoring and maintenance.

For those looking to create a more spacious and visually appealing habitat, upgrading to a 20-gallon tank or larger is advisable. The larger tank not only allows for a larger school of Glowlight Tetras but also provides the opportunity to include more plants, decorations, and hiding spots. This additional space promotes the natural behavior of the tetras, allowing them to explore, establish territories, and exhibit their vibrant colors.

It’s important to note that if you plan to keep multiple schools of tetras or create a diverse community tank, a larger tank size would be necessary to ensure ample space for each species.

How Many Glowlight Tetras Are Suitable For 10-Gallons?

Six Glowlight Tetras are suitable for 10-gallon tanks. If you get more than that, you’ll overcrowd them, leading to health issues in the fish. Six tetras are the minimum for a school, so 10 gallons should be the smallest size you consider.

Generally, one inch (2.54 cm) of tetra needs a gallon of water to thrive. That means you can fit about six tetras in a tank comfortably.

Although, you will want to add plants and decorations for them. So, many people prefer to get something a bit larger.

Remember that you can’t get a tank that’s too big for fish, but you can get one that’s too small.

Water Parameters

  • Water temperature: 74°-82°F (23.3°-27.7°C)
  • Water pH levels: 5.5 to 7.5
  • Water hardness: 6 to 15 dGH

Once you’ve chosen your tank, you must ensure the water is habitable for your Glowlights. These fish prefer living in dark, acidic water since it’s closer to their natural environment.

Water Temperature

Glowlight Tetras come from a tropical environment, so they like their water on the warmer side. You’ll need to keep the temperature between 74° and 82°F (23.3° and 27.7°C) for them.

The easiest way to do this is to use a tank heater, especially if you live somewhere cooler.

Water pH Levels

Glowlight Tetras also prefer slightly acidic water. You’ll need to keep the pH of their tank between 5.5 to 7.5. However, they prefer to be on the lower end of that range.

You’ll want to shoot for a consistent pH of 6.8, then make the water even more acidic if you want your tetras to breed.

Water Hardness

Next, these tetras want to live in soft water. They can survive in water hardness that falls between 6 to 15 dGH.

You can lower the hardness by adding sources of tannins, such as driftwood and natural plants. These materials also make the water darker, which your Glowlights will love.

Water Current

Glowlight Tetras like a bit more water current than other tetras. Their original habitat has a moderate to strong current, so these fish love playing in moving water.

You’ll want to ensure the current isn’t too fast and your fish can move from the bottom of their tank. I recommend starting with a slow to medium current and watching how they react.

There should also be areas of still water in the tank for your fish to rest and relax.

What To Put in the Tank

Next, you’ll need to know what to put in your tank. Decorating an aquarium is one of the best and most fun parts, but you must carefully choose what to include.

Natural decor will make your fish more comfortable and make their bright colors stand out even more.


First, you’ll need to choose a substrate. I recommend using sand with Glowlight Tetras. It’s very fine, so they won’t choke on it, and it more closely resembles the substrate from their original habitat. 

Darker sand is usually best since these tetras come from dark waters. Plus, dark sand can make the tetras’ red stripes appear more vivid. Dark gray, black, and brown sand are some of the best options.


Next, you must include plenty of decorations in your Glowlight tank. These small tetras need hiding places, so you should provide them with plants, driftwood, and rocks to swim through.

Another option with Glowlights is fake plants that glow under UV light since these fish can also glow under UV. Make sure there are a ton of plants for filtering the light.

You can arrange the decorations to form caves and places for the fish to peek out.

Ideal Plants

Glowlight Tetras don’t like bright light and prefer to live in low-light conditions. You’ll want to use a soft light in their tank with plenty of plants to help further filter out the light. Floating plants such as Amazon Frogbit, Java Fern, and Java Moss are the best at this.

You can also add Amazon Sword and Guppy Grass as middle-ground plants. Then, consider placing some Jungle Vallisneria in the back of the tank.

You’ll want a good portion of the tank to be planted. However, you need to ensure there is free swimming space in the center of the tank.


Glowlight Tetras prefer low lighting. So, in most cases, light from your room is more than enough for them. Adding plants can help filter out more light, which the fish will appreciate.

These tetras come from dark waters, so they usually don’t like a lot of light. Blacking out the sides and back of the tank can help darken the tank a lot more.


While your Glowlights may not need a light, they will probably need a water heater. If you live somewhere cooler, you’ll want to ensure you get one since these fish are sensitive to changes in temperature.

A submersible heater will be the best choice. I recommend this Tetra Heater because it’s excellent for 10-gallon tanks. It also stops at a set temperature for tropical fish and is very easy to hide behind decorations.


Finally, you’ll want to have some filtration in your tank. Natural plants can help keep the tank clean, so you may not need to add a filter on a small tank with a small school of tetras. However, it’s usually best to have one just in case.

Sponge filters are small enough that they won’t harm your tiny tetras. They’re the best choice for smaller tanks, although you’ll want to consider a hang-on or canister filter for larger tanks with more fish.

Glowlight Tetra Tank Mates

Glowlight Tetras are the best tank mates! They get along with most other fish and won’t bother them if you have them in an appropriately-sized school. 

Unlike most other tetras, Glowlights aren’t known to be fin nippers, allowing you to keep them with even more fish. They make a perfect community fish.

You can keep them with other fish that are peaceful and similar in size, such as:

Tank Mates To Avoid

It is best to avoid fish species known for aggressive behavior, such as cichlids and angelfish, as they may pose a threat to the peaceful nature of Glowlight Tetras. Being so small Glowlights can also end up on the menu for bigger fish. 

You’ll also want to avoid any fish known to be fin nippers to prevent stress and potential fin damage.

Glowlight Tetra Food and Diet

The Glowlight Tetra is an omnivorous species, that requires a well-rounded diet to thrive in captivity. High-quality commercial flake or pellet food formulated specifically for tropical omnivorous fish is a perfect staple for them. You’ll want to crush them up small enough for the fish to swallow as they have tiny mouths.

Incorporating live or frozen foods such as brine shrimp, daphnia, or bloodworms provides valuable variety and enhances their overall health. You can also use them for conditioning before your fish breed.

You should feed your Glowlight Tetras two to three times each day. These should be small meals that are spread far apart from one another.

Breeding Glowlight Tetras

You can breed Glowlight Tetras at home, although it can be more challenging than breeding other tetras. The Glowlights require particular breeding conditions. 

Start by making a separate breeding tank for your fish and filling it with plenty of plants. The plants hide the eggs and keep them out of direct light.

Next, you’ll need to make the water much softer and darker. The water should be at or under 6 dGH. You can soften and darken the water by adding aquarium peat. It also makes the water more acidic, which you want for a breeding tank.

You need to make the water conditions as close to the Glowlight’s natural habitat as possible to get them to breed.

Glowlight Tetra Common Health Issues

You’ll need to be aware of some common health issues before adopting Glowlights. They often suffer from Ich Neon Tetra disease (NTD) and fin rot. Knowing about these health problems can help you prevent them.


Ich (white spot disease) is a widespread health problem for any fish, including tetras. It’s a parasitic infection that can be fatal to Cardinals if you don’t identify and treat it right away.

Ich Symptoms

Your tetras will start rubbing and bumping into objects in their tank. They’ll develop white patches on their fins and body a few days later.

They can also become lethargic and won’t eat as much. If the ich is on their gills, they’ll gasp for air.

Ich Treatment

You can buy ich treatments at just about any pet shop. However, since Cardinals love warm water, you can also raise the temperature of their tank for two weeks to kill the parasites.

86°F (30°C) speeds up the parasite’s life cycle, causing it to die faster. Just make sure you don’t stop early.

Ich Prevention

The best way to prevent the spread of ich is to quarantine any new fish you get in a separate tank.

If your tetras get ich in a community tank, you must isolate them immediately and start treatment.

Neon Tetra Disease (NTD)

Neon tetra disease is an illness that’s common among many different species of tetras. It can impact the fish’s muscles and organs and is fatal. It’s caused by a parasite that spreads from sick fish.

NTD Symptoms

You’ll see white spots on the fish first, and their bright stripe will lose color. The infected tetra will start swimming strangely and restlessly during the night.

The fish will also eat less, and its spine may become curved. The disease can lead to other infections such as fin rot or dropsy.

NTD Treatment

There are no effective treatments for Neon tetra disease today, so your best option is prevention.

If you have a fish you suspect is sick with Neon tetra disease, you’ll need to quarantine it immediately. Doing so can stop it from spreading to the rest of your tetras.

NTD Prevention

Prevention is critical when raising tetras. You’ll want to quarantine any new fish you get for several weeks in their own tank. Keep the tools you use separated so there’s no cross-contamination between tanks.

Neon tetra disease is so common because tetras often are sold from overcrowded tanks where the sickness can spread quickly. You’ll need to ensure you’re getting your fish from reputable sellers.

Keeping the water quality up can also help with prevention.

Fin Rot

Fin rot begins at the outside of the fins and slowly works its way toward the fish’s body. At that stage, the decay could start to attack the tetra’s body, making it harder for it to heal the damage to its fin.

Poor water conditions and overcrowding usually cause this health issue.

Fin Rot Symptoms

The ends of the fins will become darker and start to fray. The fin may even come off the fish in large pieces and have white spots. Inflammation at the fin’s base can also be visible.

Fin Rot Treatment

A broad-spectrum antibiotic called erythromycin is the best option for treating fin rot. It can help with various bacterial infections. It also treats gill disease, mouth fungus, and open injuries in fish.

You’ll need to make sure you administer the treatment properly.

Fin Rot Prevention

Fin rot is often a result of stress or poor water conditions. Keeping your fish happy and healthy is the best way to prevent this disease.

If other fish are nipping at a fish’s tail, it could also lead to an infection that causes fin rot. So, make sure you don’t pair aggressive fish with species that they’ll bully.

Are Glowlight Tetras Right For You?

Glowlight Tetras are right for everyone. They’re peaceful, easy to take care of, and on the hardier side, making them great fish for beginners. These tetras also look beautiful and are enjoyable to watch.

So, most people love them. Beginners and experts alike can have fun raising these fish.

Glowlight Tetra FAQs

Will Glowlight Tetras Eat Shrimp?

Glowlight Tetras will eat baby shrimp. They aren’t large enough to eat the adults and will leave them alone. Anything your tetras can fit into their mouths, they’ll try to eat.

So, you won’t want to keep small shrimp in the tank. It can cause the shrimp stress, and they’ll spend most of their time hiding.

What Are the Easiest Tetras To Keep?

Glowlight and Neon Tetras are some of the easiest ones to keep. They can live in smaller tanks, are somewhat hardy, and it’s simple to care for them. Both of these species are excellent choices for beginners.

Many fishkeepers recommend trying out Neons and Glowlights for your first tetra since they’re easy. 

Do Glowlight Tetras Glow in the Dark?

Glowlight Tetras don’t glow in the dark, but they reflect their vibrant colors under UV, making them look brighter and fluorescent. Many people add fake blacklight plants that glow under UV with them for a more exciting tank.

Even though they aren’t glowing, they can appear to be. It’s a nice effect that makes these fish more appealing to many.

Wrapping Up

In short, Glowlight Tetras are lovely fish to raise. Originating from tropical climates, these fish thrive in acidic, soft water conditions and prefer subdued lighting in their tanks. With their peaceful nature, Glowlight Tetras prove to be excellent companions, harmoniously coexisting with a wide range of other fish species. 

Their vibrant colors and serene demeanor make them a wonderful addition to any aquarium setup. By providing them with the appropriate care, you can enjoy the beauty and tranquility these tetras bring to your aquatic environment.

I’m Elle, the founder of FishHQ. I created this website to share knowledge, tips, and inspiration for beginner hobbyists to help them create a healthy, happy, and vibrant environment for their fish to thrive. Read more...