Black Skirt Tetra 101: Care, Tank Mates, Breeding & More

The Black Skirt Tetra is one of our favorite freshwater species for a few reasons.

Not only do they have an interesting look that sets them apart from other fish in your tank, but they’re also a piece of cake to take care of. This makes them an approachable option for aquarists of all skill levels!

This guide will teach you everything you need to know about Black Skirt Tetra care. We cover habitat requirements, water parameters, tank mates, breeding, and much more!

Species Summary

Black Skirt Tetras (Gymnocorymbus ternetzi) are a unique addition to community tanks. While other species of the Characidae family are known for being bright and colorful, these fish take on a darker appearance. Even still, they are quite beautiful and stand out in well-kept aquariums.

These fish helm from several bodies of water in South America. They can be found in the Paraguay River Basin, throughout Brazil, and even in Argentina. They go by many different names. These include Black Widow Tetra, Petticoat Tetra, and Blackamoor.

Today, they’re a common species in the aquarium trade. They’re readily available at many pet stores due to their massive popularity. Black Skirt Tetras are relatively easy to raise in captivity. But, they do require vigilant care to stay healthy.

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Typically, the average Black Skirt Tetra lifespan is between 3 and 5 years in captivity. There have been some reported instances where these fish have outlived this average range, but it’s not common.

This fish species is affected by poor water conditions and a lackluster environment. To ensure that your fish live to the end of their life, you need to maintain the tank and provide a stress-free habitat.


Because they belong to the Characidae family, Black Skirt Tetras have that iconic tetragonal shape. They’re considerably taller at the front of the body. However, the rear end of the fish tapers dramatically to the tail. The unique shape is made more dramatic by their fins.

One Black Skirt Tetra

These fish have very distinct fin shapes. The tailfin is quite thin and features a forked shape. Meanwhile, the dorsal fin is very small and squared off. On the bottom of the fish, you’ll notice a dramatic anal fin.

It extends from the middle of the body down to the tail. It’s thicker towards the belly of the fish, creating a very quirky shape that stands out.

When it comes to color, the fins are usually dark gray or black. They are translucent and feature tiny rays. The rays aren’t as firm or pointy as you’d see on other fish species, but they are visible upon close inspection.

The main color of the Black Skirt Tetra is grayish silver. It’s translucent with the head being lighter and more reflective than other parts of the body. The fish gets its unique name from the color’s gradient effect.

Starting at around the middle of the body, that silver-gray color fades to a darker black. Two distinct black stripes are located on the front half of the body. They run vertically and complement the gradient quite nicely.

Sexing these fish can be a bit tougher than other species. The differences between males and females are subtle.

Contrary to the norm, female specimens tend to be slightly larger than males. They’re often plumper in size as well. This is especially true when the fish are breeding.

Males can be identified by looking at the anal fin. This fin is usually a bit wider than the fin on females.


A normal Black Skirt Tetra size is around 3 inches long at full maturity. Like most common tetra species, this species doesn’t get very big at all.

Author Note: It can be possible for these fish to end up smaller than 3 inches if they had poor care before you got them (or just bad genes). All you can do is provide them with the best care possible, and hope they grow big and strong!

Black Skirt Tetra Care

Black Skirt Tetra care shouldn’t be an issue for you, regardless of how much experience you have with fishkeeping or aquariums. This species is easy to please and don’t have any complex habitat requirements.

However, you still need to abide by certain guidelines. You must put their health first and stay on top of tank and water conditions to ensure that they live long and happy lives.

Tank Size

The recommended tank size for Black Skirt Tetras is a minimum of 15 gallons. This should be enough for a small group of fish to swim comfortably. If possible though, go for a 20-gallon tank for good measure.

If you plan on keeping a large group of Black Skirt Tetras or creating a community tank with multiple species, larger tanks are always better. These fish are active swimmers, so you need to provide plenty of space to prevent overcrowding.

Water Parameters

Good water conditions are paramount when it comes to keeping your fish healthy. Poor quality can lead to unnecessary stress or a wide range of diseases. This will significantly affect the health of this species, and even lead to death.

A good rule of thumb for any fish is to replicate the water conditions of their natural habitat. The bodies of water in South America that these fish live in are warm and slightly acidic.

Here are some important parameters to stick to when you’re setting up a tank for Black Skirt Tetras.

  • Water temperature: 70°F to 85°F (aim for the middle of this range)
  • pH levels: 6.0 to 7.5
  • Water hardness: 4 to 8 dKH

It’s a good idea to invest in a reliable water testing kit to be sure you’re getting accurate readings. Even though these fish are rather tough, any significant shift in water parameters can lead to serious health issues.

What To Put In Their Tank

Decorating the tank is where you can get a little creative! The ecosystem where these fish reside in the wild is teeming with life. You can recreate that in your own tank and experiment with your own aesthetic preference.

Plants are one of the most important things to introduce into the aquarium. Black Skirt Tetras love big plants that they can explore and swim through. In the wild, the fish feed off the plants as well. Having some hardy ones in your tank can be a nice snack for your fish in between feedings.

We recommend taller plans ideally. Black Skirt Tetras typically stick to the middle of the aquarium. Taller plants will ensure that the fish have places to hide without having to venture down to the bottom of the tank.

Gymnocorymbus ternetzi in a well-planned tank

When you’re arranging vegetation in their tank, don’t overdo it! The plants shouldn’t be too dense. Remember, these fish are active swimmers and need some room to move freely.

The best way to go about this is by keeping the plants in the background and perimeter of the tank. This is an effective method for providing enough open space for this species.

But what about the rest of the aquarium?

At the bottom of the tank, you can use a dark sandy substrate. River gravel works, too.

These fish won’t go to the bottom of the tank very often, so this isn’t a huge decision. However, darker colors will accurately mimic the decaying leaves at the bottom of the streams they call home in the wild.

You can add cave systems and driftwood as well. These make great hiding spots for whenever the fish are feeling a bit shy or threatened.

A strong filtration system is a must. While they don’t produce a ton of waste individually, a large school can quickly alter the water quality. Your filter should be capable of keeping ammonia and nitrate levels relatively low and get rid of all forms of waste.

Author Note: To improve water quality even more, we recommend replacing 25 to 50 percent of the water every other week. This will dramatically improve water quality in the long run.

Common Possible Diseases

Like any other freshwater fish, Black Skirt Tetras are prone to a variety of diseases. Your fish could experience Ich, which is a parasitic infection that’s brought on by stress. It causes visible white lesions throughout the entire body.

If not dealt with promptly, Ich can be fatal. In most cases, poor water conditions are the primary cause of stress-related Ich. You can reduce the chances of Ich problems by performing water tests regularly and making the necessary changes.

Ich is not too difficult to treat. Though, it’s highly contagious. Infected fish must be separated from the rest of your fish and treated with a copper-based medicine.

Black Skirt Tetras are also at risk for fungal and bacterial infections. The most common are Dropsy, fin rot, and Fish Fungus. Most of these issues can be treated by improving water quality and using over-the-counter medications.

Author Note: If none of these diseases sound particularly fun to you (spoiler alert: they aren’t) then your best bet is to become a water quality fanatic. The chance of your fish getting sick goes way down if the water they live in is clean and taken care of.

Food & Diet

Black Skirt Tetras aren’t picky when it comes to food. In the wild, they will feed off plants and consume pretty much any insects they come across.

In captivity, this species should do just fine with a diet of commercially-available dry food. You can provide nutrient-rich flakes or pellets for their main meals.

Many hobbyists like to supplement dried or frozen food with live food. Black Skirt Tetras love snacks like bloodworms or brine shrimp. These will give them some variety and enrichment which will keep their stress levels low.

Behavior & Temperament

Black Skirt Tetras are quite easy-going and peaceful. They will rarely exhibit signs of aggressive behavior no matter what the situation is. The only thing you need to be wary about is their actions around long-finned fish.

We say this because this species is prone to nipping at flowy fins of betta fish or angelfish. Other than that, Black Skirt Tetras can get along with other peaceful fish without any issues. 

As far as their daily activity and behavior is concerned, these fish will spend most of their time swimming around the tank and generally being curious.

This is a schooling species, so they tend to stick together throughout the day and swim in unison. However, they may go off and do their own thing every once in a while before returning to the group.

Black Skirt Tetra Tank Mates

Because they are shoaling fish, we recommend that you keep a decent group of Black Skirt Tetras together.

At the very least, you need a group of 5 fish to keep them happy. However, we recommend getting even more if you have space for them!

A larger group makes the fish feel more comfortable and confident in their surroundings. In situations where this species has exceeded its expected lifespan, they’ve almost always been in a big group.

As far as other species go, you have a lot of options when it comes to Black Skirt Tetra tank mates.

Try to avoid fish that show signs of aggression (the more peaceful the better). This is because Black Skirt Tetras can become targets due to their passive nature. Plus, their long fins are the target of fin nippers.

The funny thing is that this species tends to nip when they have the opportunity as well. For that reason, we recommend avoiding any long-finned fish species.

Here are some of our favorite compatible species that make good Black Skirt Tetra tank mates:


Black Skirt Tetra breeding isn’t too difficult. However, it does require a bit of work. These fish do not care for their eggs or the baby fish fry at all. So, you must breed them in a separate tank to prevent the adults from eating the babies.

You can set up a separate 10-gallon breeding tank. Use the same water parameters and introduce some plants into the mix. We recommend using a spawning mop, artificial grass, or a net.

These accessories can be used to hide the egg and provide some separation after the breeding process. The goal is to make it difficult for the adult fish to feed on the eggs.

When you’re ready, separate a bonded pair and place them in the breeding tank. Feed the fish protein-rich live foods until you see the female start swelling up with eggs.

At this point, the male fish may start to chase the female around. Keep an eye on the two fish and make sure that the male isn’t being too aggressive. If he causes harm, separate the fish for the time being.

If successful, the female will start laying up to 1,000 eggs all over the tank. Black Skirt Tetras will scatter their eggs throughout the entire tank instead of choosing one spot. The eggs will then sink to the bottom.

That’s why it’s a good idea to have some kind of grass or mesh netting. The eggs will fall through to the bottom where they will be hidden from the adults as they continue to breed.

After they are done, return the adult fish to the main tank. The eggs will hatch in 24 to 36 hours. The baby fish will feed off the egg sac when they first emerge. Several days later, you can provide powdered fry food or infusoria.

In a couple of weeks, they will be big enough to consume baby brine shrimp. Keep the fry separate until they are large enough to not be consumed by other fish.

Taking The Next Step

Now that you’re familiar with the principles of Black Skirt Tetra care, it’s time to get one for yourself!

These fish are quite fun to own and we recommend them to fellow aquarists all the time. Their unique look and consistent activity level make them a great species to spectate.

If you have any suggestions on ways we could improve this care guide please get in touch with us. We’re constantly looking for new ways to make the information on our site even better!

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