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Black Skirt Tetra: Everything You Need To Know

Black Skirt Tetra: Everything You Need To Know

Whether you’re new to fishkeeping or an experienced aquarist, this complete Black Skirt Tetra care guide will help you keep your fish happy and healthy. While this fish species is hardy and relatively easy to care for, they do have specific needs.

Black Skirt Tetras (Gymnocorymbus ternetzi) are omnivorous, schooling tropical fish that require a 15–20-gallon (57–76 L) tank, warm temperatures around 70–85 °F (21–29 °C), 6.5–7.5 pH, and relatively soft water conditions. Black Skirt Tetras can be territorial but do fairly well in community tanks.

This article will explore Black Skirt Tetra care in-depth. This guide includes discussions about their behavior, diet, environment, diseases, tank mates, breeding, and more. 

Black Skirt Tetra 101: Species Overview

  • Common name: Black Skirt Tetra
  • Scientific name: Gymnocorymbus ternetzi
  • Care level: Easy
  • Size: 2–3 inches (5–7.5 cm)
  • Lifespan: Up to 5 years
  • Temperament: Semi-aggressive
  • Diet: Omnivore
  • Group size: 5 or more
  • Minimum tank size: 15–20-gallon (57–76 L)
  • Tank level: Mid-top dweller
  • Water temperature: 70–85 °F (21–29 °C)
  • Water pH: 6.5–7.5
  • Water hardness: 4.0-8.0 dKH

Black Skirt Tetras are small tropical fish belonging to the Characidae family. They’re native to the rivers of Rio Paraguay, Rio Guapore, and Bolivia.

Typically Black Skirt Tetras inhabit the upper portions of the water column, preferring slow-moving bodies of water that mimic their natural habitat. They thrive in shaded environments that don’t have direct sunlight.

With their unique Characidae shape and gradient coloring, these attractive fish will undoubtedly add vibrancy to your community tank.

Black Skirt Tetra Appearance & Size 

Black Skirt Tetras are recognizable by their tetragonal shape, similar to a rectangular prism cube.  The front of their bodies are noticeably taller than the back which tapers significantly toward the tail.

Black Skirt Tetras are small fish, growing to about 2–3 inches (5–7.5 cm) in length, and have dark silver bodies with 2 vertical black stripes and black or charcoal-colored fins.

As they mature their dark colors start to fade, and as they approach the end of their lifespan, around 5 years, they become significantly paler.

Difference Between Males and Females

Telling the difference between male and female Black Skirt Tetras isn’t the easiest as there aren’t any significant differences. The male has a larger anal fin than the female, whereas the female tends to grow a little larger and rounder than the male. 

Aquarium-Bred Variations

Although the Black Skirt Tetras found in pet stores are identical to those in the wild, they come in other aquarium-bred variations. These include the following:

  • Long Finned Black Tetras look similar to the wild-caught variety, but their fins are longer and often darker. 
  • Gold-Skirt Tetras (or white tetras) are golden to pale yellow across their entire bodies. 
  • Colored Skirt Tetras come in pastel blue and pink colors. Both gold-skirt and colored-skirt tetras come in long-fin varieties. 
  • Glo-fish is a captive-bred long-fin variety produced through genetic engineering. They come in several neon colors that luminesce under black light. 

Regardless of variety, their care and lifespan are the same. These tetras are active swimmers and relatively peaceful when kept with other active fish.

Black Skirt Tetra Personality & Behavior

Black Skirt Tetras are fast-swimming schooling fish. This means they thrive in groups of five or more. In fact, the more they feel secure and happy in large schools. 

Those kept in groups of less than five may have shortened lifespans and increased health issues due to stress. 

These fish are active swimmers who tend to hang out mid-to-surface level in the tank. They enjoy having open swimming spaces and large plants to hide in when spooked. 

Contrary to popular belief, these fish are semi-aggressive. They can be territorial in smaller tanks and especially when breeding.

Black Skirt Tetras should, therefore, only be kept with peaceful, fast-moving tank mates in aquariums larger than 20 gallons (76 L). 

Black Skirt Tetra Average Lifespan

Their lifespan in captivity is around 5 years when cared for properly.

Make sure you take care to maintain their tank to provide a stress-free environment so these lovely fish live a long, healthy, and happy life.

Black Skirt Tetra Care & Tank Set Up

One of the reasons Black Skirt Tetras are so popular amongst aquarists is their relatively easy care. They don’t require any special equipment or unusual water parameters to thrive. They also adapt well to water parameters outside their ideal conditions, which makes them easy to keep with fish from disparate environments.

Aquarium Nitrogen Cycle

The nitrogen cycle is one of the most important aspects in fishkeeping.

A common mistake for beginners (new tank syndrome) is not knowing about the nitrogen cycle or not keeping it in mind when maintaining the water.

The nitrogen cycle is the process by which beneficial bacteria convert fish waste and uneaten food in the aquarium into less harmful substances. The cycle is crucial for maintaining a healthy and stable environment for fish and other aquatic animals.

In new aquariums, there may not be enough bacteria to break down fish waste, resulting in an unhealthy buildup of ammonia and nitrite. This is not visible to the naked eye, so it’s important to regularly test the water with a kit to ensure the smoothness of the nitrogen cycle.

Failing to complete regular nitrogen cycles can lead to the accumulation of harmful substances like ammonia and nitrite. These substances can cause stress and damage to fish, leading to health problems and if left unchecked it will eventually kill everything in your aquarium.

By maintaining a healthy nitrogen cycle, you can ensure a long and healthy life for your fish. Remember to always keep the nitrogen cycle in mind when caring for your aquarium.

Tank Size

The minimum tank size for black skirt tetras is 15-20 gallons (57-76 L). Because they must be kept in groups of five or more, a larger tank is always better. 

A general rule of thumb in aquarium size is to have a minimum of 1 gallon (3.8 L) of water per 1 inch (2.5 cm) of fish

Since Black Skirt Tetras can grow up to 3 inches (7.5 cm) in length, even a 20-gallon (76 L) tank will eventually be overcrowded when the fish reach maturity. This is especially true if you keep a larger school or add other tank mates. 

Keeping young Black Skirt Tetras in a 20-gallon (76-L) tank is okay. However, you must upsize your aquarium within six months. Doing so will help prevent poor water conditions, health problems, and stunted growth due to overcrowding. 

Alternatively, you can move some of the fish to another tank. Just ensure there are at least five of them in each aquarium. Otherwise, they will exhibit signs of stress and poor health.

Water Parameters

  • Water temperature: 70-85°F (21-29°C)
  • Water pH: 6.5-7.5
  • Water hardness/dKH: 4.0-8.0
  • Ammonia: Under 2 ppm
  • Nitrites: 0 ppm 
  • Nitrates: 0 ppm

Luckily, Black Skirt Tetras are pretty adaptable regarding water parameters. 

However, it’s worth noting that although Black Skirt Tetras can still live healthy lives outside the parameters, they may not live as long. To maintain peak health and lifespan, it’s best to provide them with an environment as close to their native one as possible.

That means warm temperatures, near-neutral pH, and soft water.

What To Put In The Tank

The best way to set up your aquarium for Black Skirt Tetras is to mimic their natural environment. You can do so by using a dark-colored substrate, creating an open swimming space, and installing large leafy plants to hide in. 

The best configuration is to arrange plants around the back and sides of the aquarium walls, leaving the center open for schooling. 


There are several substrate options that look natural and will effectively mimic the river habitats of Black Skirt Tetras. However, if an unnatural look appeals to you, your tetras should be happy so long as their basic needs are still met. 

Make sure that whatever substrate you buy, it should be specifically designed for aquarium use to ensure that it doesn’t negatively affect your water quality or fish.

You can refer to some examples below:

  • Aquarium gravel: This classic rocky substrate is typically found at pet and aquarium stores. It comes in various colors and sizes, from tiny pebbles to medium ones. 
  • River stones: Similar to aquarium gravel, river stones are tiny rocks in various colors and sizes. However, they are smoother and usually come in natural colors like brown and gray. 
  • Aquarium sand: This substrate also comes in various colors, but it doesn’t allow water to flow underneath, which limits the growth of healthy bacteria. However, waste and debris will sit on the surface, making it easier to siphon away. 
  • Aquarium soil pellets: These look like little brown or black balls and are typically composed of clay and other materials. They are designed to support the growth of natural aquarium plants without dirtying the water. 

Many aquarists use a combination of two or more of the abovementioned substrates to create the look and function they desire.

Live Plants

Live plants are an excellent addition to any aquarium because they help clean the water and make fish feel at home. 

The best live plants for black skirt tetras grow tall or large and provide plenty of cover. As long as there is foliage they can swim in and out of, your tetras will be happy. 

Below are five easy-care live plant options that don’t require strict soil or water parameters:

  • Java fern (Microsorum pteropus): This is a hardy, slow-growing plant with long, thick leaves. It will thrive even in low-light conditions. 
  • Amazon sword (Echinodorus amazonicus): This plant is a tall, adaptable plant with broad, pointed leaves. The foliage is suitable for Black Skirt Tetras to swim through. 
  • Wendt water trumpet (Cryptocoryne wendtii): A vibrant plant with low, wide-spreading rosettes of bright green leaves, this plant is tolerant to almost any environment but needs root tabs or soil pellet substrate to flourish. 
  • Bacopa (Bacopa caroliniana): It’s a flowering plant with a tall-growing stalk and small rounded leaves. It’s easy and fast-growing when given good light and liquid fertilizer. 
  • Vallisneria (Vallisneria spiralis): This is a grass-like plant with bright green blades. It grows fast once established and benefits from both root tabs and liquid fertilizers. 

If you choose to use an inert substrate (gravel, rocks, sand), you must purchase some aquarium plant fertilizers to help these plants grow.

The Seachem Flourish Freshwater Plant Supplement (available on is suitable for the plants listed above. It can nourish your aquarium plants without harming your fish. For best results, always follow the instructions on the product label.


While Black Skirt Tetras don’t require driftwood or other structures to be happy, adding some can provide extra cover in addition to plants. They can also provide visual interest and make your aquarium scape very pleasing to look at.

Keep in mind that driftwood can change the quality of your aquarium water. Wood releases tannins, lowering pH and discoloring aquarium water, but it won’t harm your tetras. Using activated carbon in your filtration will help control any discoloration.  

Below is a list of driftwood varieties you can easily purchase online or at aquarium supply stores. These varieties are the least likely to leach tannins and discolor your water. 

  • Cholla wood: This is the most affordable type of aquarium driftwood. It comes from cacti and has low to moderate tannins. Its hollow, perforated structure provides a lot of visual interest. It can take some time to become saturated enough to sink.
  • Manzanita: This driftwood variety has attractive, tree-like branch structures and low tannins. It’s one of the few driftwood types that don’t change water pH. 
  • Spider wood: Also known as Azalea root, this wood has an interesting spider-shaped structure that makes for attractive scaping. It’s also low in tannins
  • Tigerwood: This variety has larger, longer branches than other types of driftwood. It also has low tannins. 

Note: Never use items you find at the beach or in nature. They may contain bacteria and other contaminants that could pollute your aquarium water and harm your fish. 

Other Aquarium Decorations

If live plants and natural driftwood aren’t for you, plenty of artificial alternatives are readily available. Adding some artificial plants to your aquarium in place of live ones is a good alternative but entirely optional.

Here are some things to consider:

  • Plastic plants: These come in many colors and varieties. Some mimic natural plants and others look fantastical or glow in the dark.
  • Ceramic caves: These can look natural or fantastical. Many pet supply stores carry a wide variety. 
  • Ceramic or terracotta pots: Small, unglazed pots are best. You can buy them from any garden supply store and use them to create caves in your aquarium or even plant your aquatic plants in them. 
  • Ceramic statues: These should be designed specifically for aquariums, as you want to be sure they are made of fish-safe materials. 
  • Rocks: These come in many attractive varieties and can be used to build caves and other structures inside your tank. Buy from an aquarium store to be sure you’re getting clean, fish-safe materials. 

Note: Rocks you find in nature may add unwanted contaminants to your aquarium water. Natural aquarium rocks can also affect water quality by leaching minerals. This effectively raises the water’s hardness. 

A slight increase in water hardness shouldn’t be a problem for Black Skirt Tetras unless your aquarium water is already high on the hardness scale. 

Black Skirt Tetra Tank Mates

Black Skirt Tetras are semi-aggressive schooling fish. They may show territorial behavior, nipping fins and bullying smaller, slower fish. For this reason, the best tank mates for these fish are peaceful, fast-swimming species.

Other schooling fish species are ideal, but remember that the more fish you stock, the larger the tank must be. Keeping a school of Black Skirt Tetras in a community tank means you will need more than 20 gallons (76 L) to avoid overcrowding. 

Since Black Skirt Tetras tend to swim in the upper half of the tank, bottom dwellers like loaches and catfish can be excellent choices. 

Below is a list of suitable species for community tanks with Black Skirt Tetras:

Tank Mates To Avoid

Black Skirt Tetras will nip the flowy fins of other fish, particularly long-finned and slow-moving species. So you’ll want to avoid fancy guppies and bettas

Black Skirt Tetra Food & Diet

Black Skirt Tetras are omnivores. That means they need to be fed both vegetable-based and protein-based foods. You can purchase omnivore food flakes at any pet store, but choosing a high-quality brand is vital. 

Check the ingredients label and choose fish food with as few ingredients as possible. Avoid foods with lots of additives and fillers. 

The first few ingredients should be shrimp, krill, fish meal, or other seafood. Choose one with top ingredients like spirulina and other vegetables for herbivore flakes. 

Remember that even though they are omnivores, their diet should be no more than 35-40% protein. Feeding too much protein can result in fat fish with health issues and shortened lifespans. 

For this reason, the main component of your Black Skirt Tetras’ diet should be high-quality vegetable-based flake food

In addition, your tetras will live longer, healthier lives if you supplement their diet with live, fresh, and frozen foods

Freeze-dried foods are good for dietary supplementation and occasional treats. Still, they lack the nutritional punch of frozen, fresh, and live foods. 

Good live and frozen foods for Black Skirt Tetras include the following:

  • Brine shrimp 
  • Blood worms
  • Micro worms
  • Infusoria
  • Daphnia
  • Blackworms

Feeding Schedule

Feed your Black Skirt Tetras twice daily, providing only as much food as they can consume in 3-4 minutes. Remove uneaten food from the tank to avoid polluting the water. 

Live foods can remain in the aquarium until they are consumed. 

Breeding Black Skirt Tetras

Black Skirt Tetras are not difficult to breed if you provide the right environment. However, these fish are egg scatterers, so keeping them in isolated breeding tanks is best. This will prevent other fish from consuming the eggs and fry. 

Black Skirt Tetras can be bred in groups, but the tank must be large enough to prevent aggression. Each pair will fiercely defend their breeding territory.

Breeding tank parameters must be as follows: 

  • Dim lighting (eggs and fry are sensitive to light)
  • Java moss or another soft substrate to catch the eggs
  • A stable temperature range of 82 to 86 °F (28 to 30 °C)

Black Skirt Tetras will eat their eggs and fry, so remove them from the breeding tank as soon as they have spawned.

Allow the eggs to mature and hatch without disturbing them. You can feed the hatchlings infusoria until they are large enough to eat other foods. 

Black Skirt Tetra Common Health Issues

Black Skirt Tetras are very hardy when provided with proper care and water parameters. Still, there are some common illnesses to watch out for. 

Generally, it’s essential to observe your fish daily and get used to their behavior patterns. Knowing your fish’s normal behavior can help you catch illness quickly, preventing more severe symptoms and even death. 

The first signs of illness include the following: 

  • a change in behavior
  • lethargy
  • unusual swimming patterns
  • lack of appetite

Illness is almost always a result of poor water conditions and stress, which result in lowered immune systems in fish. Everyday stressors include:

  • attacks and injury by other aggressive fish
  • overcrowding
  • poor quality of food
  • infrequent water changes

Here are common diseases to watch out for with Black Skirt Tetras:


This condition is caused by fungi that appear as small, fuzzy white dots on the fins and body. 

Treatment includes water changes and raising the water temperature to 82 °F (28 °C) or higher for a week or two. If your tetras are housed with fish that cannot withstand this high temperature, invest in some aquarium salt and antifungal treatment.

Fin Rot

This is a bacterial infection that eats away the fins. Usually, this infection starts with an injury. The fins will begin to look tattered, and/or the edges will turn milky in color. Treatments include water changes, removal of stressors (like other aggressive fish), and antibiotics.

Removing aggressive fish from community tanks is also important, as injuries are often the entry point for potentially fatal bacterial and fungal infections. 


Dropsy is a condition that results in abdominal bloating in fish caused by bacterial infection. It’s best to isolate fish that exhibit disease symptoms. Treatments include water changes, aquarium salt, and high-quality food to boost the immune system. 


Remember that these are only three of the most common illnesses your fish may suffer from. There are many others. The best way to avoid them is to:

  • keep your water conditions optimal.
  • avoid overcrowding.
  • feed fish with high-quality food.
  • do regular water changes. 

Wrapping Up

Black Skirt Tetra is an excellent tropical fish for aquarists of all experience levels. These handsome schooling fish make good community tank citizens and flourish in various temperatures and water parameters. 

They are hardy, attractive, and easy to care for. They even come in fantastical color variations that glow under black lights!

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...