The black skirt tetras are a school of fishes moving with uniformity in your fish tank.

Black Tetra is a bit of black beauty that swims with elegance in freshwaters. These are an excellent choice for home aquariums with their small and glittering body.

It acquires this striking name because of the anal fins that form the shape of a long skirt, while they are also called black widow tetra due to the black color that pales later to maturity.

The fishes are part of the fish family that belongs to the tropical & sub-tropical regions, particularly the Central regions of South America.

A notable fact is that tetras are one of the few members of the Characin family that possess roots from the yesteryears. At the same time, most of the other species have already gone through taxonomic changes. 

Learn more valuable facts about the Black Skirt Tetra in the article below.

Quick Review

Species Facts
Scientific Name Gymnocorymbus Ternetzi
Other Common Names Black Tetra, Black Widow Tetra, Blackamoor, Petticoat Tetra, Butterfly Tetra
Family Characidae
Origin South and Central America
Lifespan 3 to 5 years
Size 7.5 cm (Max.)
Habitation Freshwater

Skirt Tetra’s Origin and Habitat

They are primarily found in the freshwaters of Paraguay but are commonly seen in some parts of Central Brazil, North Eastern Argentina, Bolivia, and other connected regions.

It is even found in the Madeira river basin. The research done by experts in 2015 proved the existence of black skirts in the Guapore river is due to the main river Madeira that flows a long way to the Amazon river.

The small tributaries of South American rivers that move across the continent covering the forest areas provide essential food to the fish.

Author Note: Despite originating from the forest covers promoting wild nature, these fishes are well modified to be kept in home aquariums, where they settle down nicely.

The black widow mainly prefers warm water and loves swimming and relishing between the natural plantations. They comfortably habitat in still waters or slow movement under the dense shades while feeding tiny insects or worms.

What is the Maximum Size?

More than 30 tetra fish species were recognized, and with a slight difference in shape and color, these attain an average size between 1 inch to 4 inches.

The black tetras are ubiquitous little aquarium pets, and because of their small size, a group of them can adjust in 1 tank.

The maximum size that a black skirt can acquire is about 3 inches, but this species rarely achieve the figure. The average growth size is 2 inches, but its total length can increase with intense care and nutritional food. 

Shades and Shapes

At a glance, these pretty little tetras look like a shining star moving here and there.

Though the name suggests black coloration, the actual shade of the fish is slightly greyish silver. They look pretty dazzling with a translucent head over a darker shade body.

Two stripes or bands on the back of the black tetra’s body make it look attractive as they divide the fish into two half vertically from the front.

Pro Tip: Do not get trapped into the hands of fish sellers providing unique pink, blue, or rainbow-colored tetra. Nothing exists as the coloration is an artificial dye, only for public attraction. These are undoubtedly harmful to fish.

The fish has a typical tetragonal shape that turns conical towards the tail fin, which is enlarged and spread. This, along with anal fins, gives a magnificent style to the fish, similar to a ramp model with decorative pieces.

The long fined black skirt tetra has minute lines like veins that run across the body to display a dark silverish feather touch. This color of the fins eventually fades away with aging.

A popular variant of black skirt tetra is the white skirt tetra, which possesses almost the exact characteristics of the earlier one. The only difference is that the fish is white or pale in its appearance.

The lifespan

The black tetra usually enjoys a short life compared to other fishes in the tank.

The average life of these fish living in the wilderness of South America is not more than 6 to 7 years. Since the open waters provide multiple resources of natural habitation, it allows the fish to learn & struggle for life.

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While in-home fish tanks, the fish does not have to deal with starvation or predators. But the life expectancy lowers down to 3 to 5 years.

This downfall is mainly related to food infection, bad water conditions, stressful environment, etc.

Gender: Black Skirt Tetra Male or Female

It is never that easy to find differences between the male & female black tetra fishes.

Although these fishes appear with sure distinguishing signs during the mating season, experts have sighted few features that define the noticeable difference between the two, even at other times.

The female black skirt tetra is bulkier in size with almost a rounded or oval body structure, mainly when they breed. In contrast, the males look the same as skinny & stretched.

 Other differences observed in the female fish are vertical lines or strips running along the anal fins. On the other hand, the males have large anal fins with white dots appearing over the caudal fins.

Price Range & Availability

The black skirt tetras are easy to pet and successfully survive in normal conditions. These are exported all around the World from the source country, South America.

Though the fish is not very popular among the elite group of fish lovers,

They are usually purchased to create a variety of colors in the tank.

The average price of black skirt tetra in the international market ranges between 2$ to 5$, depending on the local taxes.

Care Guide for Black Tetra

Quick Care Sheet
Care Level Easy to moderate
Social Behaviour Stays in community
Temperament Soft Nature
Food Habit Omnivore (Eats everything)
Breeding Process Egg Layer


Black tetra is among the most convenient fish to feed in aquariums. These are omnivores naturally and accept all sorts of fish foods available in the market. This includes explicitly non-veg diets.

You can pour live insects or worms, frozen or dried food, and even flakes into the tank, but it is advised to keep a check on their health standards and provide a variety of nutritional foods, exclusively flakes.

Including the regular meat food and supplements, they are ready to consume green plants, algae, and vegetables such as spirulina. Some of the most preferred items you can feed the black skirt tetra are given in the list below.

  • Flakes
  • Pellets
  • Larva
  • Brine Shrimp
  • Bloodworms (Frozen and Live)
  • Insects
  • Daphnia
  • Vegetables
  • Seaweeds & plant matter

Pro Tip: Do not overdose these fishes with meat. Instead, you can provide supplements on alternate days to keep them healthy.

Behaviour & Temperament

The general temperament of this black skirt is friendly and polite in swimming mutually with other fishes in the tank and are seen flocking around in groups of the same variant.

They avoid confrontation in every situation and are busy in their movements or hiding behind the bushes or rocks. They leave the group for any specific activity but tend to return quickly.

But though being a tetra breed, they are not always peaceful in the presentation. At times, they behave aggressively to other communities’ fishes, particularly ones with long fins.

Another aspect of aggression is observed during the mating season when the males show grievances. Otherwise, these black skirt tetras are harmless.

Breeding & Mating

It is a tedious job to arrange a breeding environment for black skirts. These are typically ignorant and uncaring mates as they do not show any attachments to the eggs & fry.

These fishes do not have trouble breeding in artificial water bodies, but the fishkeeper has to work a lot in creating favorable situations.

Mating Setup

You can put around 4 to 5 pairs of these fishes in a medium-sized tank of a capacity of 15 Gallons and keep the warmth around 20 degrees Celsius, with proper oxygenation level.

For gesturing natural surroundings, you may put up live green aquarium plants that are bushy as they attract such mates for hiding.

Artificial mops or spawning mops are pretty popular in fish breeding as they successfully catch the eggs that the fish spread during the breading process. You can install these mops in your tank, with some rocks & pebbles, which are also helpful for this purpose.

The adult fish may not find the eggs, accidentally falling over the substrate, and it gets protected for hatching instead of becoming food for parents.

Breeding Process

Now you can induce the mating pairs into the breeding tank. It is generally advised to raise the tank’s temperature a few degrees in cold areas and then bring it down to the normal state once the fish settles down.

The male black tetras show aggressive movements while chasing the females and claiming their spawning zones.

Quick Tip: Breeding may take around a week, and in this period, you should ensure that the fishes are well treated with excellent vitamin-rich food. You will observe this when the body color glitters and darkens.

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Eggs Hatching

Once the spawning and fertilization, you can remove the adults from the tank. Else, they will start eating the eggs. For this, you need to monitor the tanks attentively and watch out for the eggs.

Black Tetras habitually spread the eggs collected into the spawning mop. You should remove the unfertilized eggs in the tank as they start attracting fungus infection.

The eggs hatch in a day and take almost 3 to 4 days when the fry comes out. It matures within a month, but the color effect appears in a year.

Author Note: Feed the fry with micro worms or liquid food for four days. Later they can small shrimps for at least a month, after which you can give them adult food items.

Common Health Issues

Black tetra is a hard skin fish as it has developed high survival instincts while dealing with the challenging environment of the tropical forests. But being a living organism is always a potential risk of infection and illness through multiple sources.

The diseases acquired by these species can be classified into the following categories.

Note: You should regularly monitor your black tetra’s daily dietary habits. There are cases recorded when they could not open their mouth to eat and suddenly started looking thinner. You must immediately visit the specialist for health advice for your fish.


This is the most common illness when small white spots occupy the whole body, especially over the fins. It happens primarily due to unhygienic water conditions causing parasites or sometimes environmental stress.

The disease is treatable by medication or raising the temperature slightly, which naturally kills the parasites, thereby curing the disease.


It is caused by infected worms eaten by the fish, which causes blisters with mucus on the body and the scales turn reddish.

It can be treated by filtering the water using either the filtering system or potassium.

Bacterial Infection

There is a list of diseases caused due to bacterial infection.

Fin Rot, Tail Rot: It is caused due to impure or unhealthy water leading to rotting fins while the fish starts avoiding food and sits to the bottom.

The initial treatment keeps changing the water at regular intervals with ammonia and pH level monitoring.

Dropsy: Unclean fish tanks usually cause such diseases when the black tetra’s body starts swelling and troubling the kidneys. The best option is to treat them with antibiotics. You can also choose a self-cleaning aquarium, for fuss-free cleaning.

Note: The swelling bellies are sometimes confused with dropsy when female fish develop eggs. The fish with dropsy will not feed well. To be sure if it is dropsy, you can self-analyze the fish’s eating routine.

Red Pest: The whole body, including the fins, displays red spots due to internal bacterial diseases. And should be treated using antibiotics.

Swelling the eyes or abdominal infection is also a common disease caused by bacteria.

Protozoan disease

Velvet disease is a common protozoan infection when the fish body acquires yellow clouds of dust over the body with cloudy eyes.

Tank Recommendations

Quick Tank Details
Tank Size 12+ Gallons 
Tank Dwelling Areas Prefers middle to top levels
Water Temperature 20 to 26 degrees Celsius
Water Hardness 5 to 19dGH
Water Ph Level 6 to 8.5

Suitable Tank Size

Considering the size of Black Skirt tetras with their nature to adapt and adjust in most situations, these fishes can thrive well in tanks of 10 Gallons water capacity.

But we being an expert in the fishkeeping industry, would suggest you keep at least four pairs of this species together in a tank. These fishes stay stress-free & healthy when they move together in a group.

These fishes spend the day swimming on the water surface so that an extended area would suit them more. So technically, the tank you will set up should be approximate—20 Gallons capacity.

Note: Don’t be surprised to see the mature fishes aggressive towards the young ones or nipping their fins. This is temporary and usually happens during the mating season. You can put off this struggle by using a bigger tank.

Proper Tank Setup

Black Skirt fishes are highly susceptible to staying in a bunch of the same variant. Ignoring a few instances of grudges to some category of long fins, they accept the company of all medium-sized fishes.

You can try putting any of the below-given suggestions into your fish tank. It will help keep them calm, active, and playful.


Natural greens attract all the animals, and so you can put in some plants that are tall in size. The fish can move through the leaves and branches, anticipating a natural dwelling.

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You can plant them next to the tank’s wall, letting the fish enjoy open space.


The fish usually stays at the top and do not show any specific need about the bottom. Few pebbles or pieces of live rocks would do the rest.

A layer of sand will create a natural persona.


Some amount of light is always required to grow both plants and fish. Black tetras do not like much light, so you can opt for low light with an adjustment system.

Water Filters

A water cleaning system is necessary to keep the fish healthy so that you can get a nice set of filters that will keep the parameters in check.


An oxygenation system is necessary to supply proper oxygen into the tanks.

Water Conditions

Water is one of the primary needs of a living being and has the power to change one’s health conditions from good to bad and vice-versa.

Each variety of fish has regular water checks required, similar to their originating places.

While creating a tank setup for your black tetras, you must carefully observe the water quality and maintain the corresponding scales, as we define here.

The required pH level is 6 to 8, while the temperature should be maintained around 68 to 78 degrees Fahrenheit (to match the subtropical climate), and the hardness should be kept under 20 dH.

The Ammonia level should be 2ppm while the harmful nitrates & nitrites level should be 0ppm.

Compatibility With Tank Mates

Black Tetras easily collaborate with other fishes to stay in a single water space. They are peaceful by nature but may display aggression towards some mates.

While being in groups, they are seen to give minute signs of aggression, but otherwise, the fish is calm and sweet in their attitude.

These are multiple fishes that can go along with black tetras but prefer only the short-finned, slow-moving, harmonious fishes. A few examples are given below.

Frequently Asked Questions

Are black skirt tetras fin nippers?

Fin nipping is an unusual activity when the fish starts eating log fins of other fishes, probably to show their commanding nature.

Though friendly by nature, Black tetras tend to nip fins of other fishes, preferably those with long fins, and sometimes fishes of their community.

Is it healthy to feed black tetras in an aquarium with live food?

Yes, in fact, live insects, worms, and shrimps are the preferred food of these fishes in the wild arena. But at times, it is difficult to arrange such foods in the aquarium, which is when you can supplement it with flakes, pellets, etc.

There are chances that the live organism provided carries some infection and is potentially risky for the fish in the aquarium. So be careful while feeding with such choices.

How many eggs do the female black skirt tetra fish lay at a time?

The Female black tetras lay up to 1000 eggs at a time and scatter them all around. With this number of eggs in the belly, the fish size looks enlarged until they lay eggs.

Why does Black Tetra lose the shine and shade?

There can be two reasons for the fish to lose its color& shine. Either the fish is aging towards five years or more when it is normal for the black tetra to get pale. Another reason for discoloration is when the fish is unhealthy.

Why do some black tetras start getting darker in the shade?

The black skirt tetras start getting darker because either they are in their mating season or are in a stressful situation. Leave them if they are about to mate while trying to improvise the environmental conditions to remove stress and calm them down.

When do the black skirt tetras swim over the top surface of the tank?

Black tetras usually swim at the top when the oxygen level lowers in the water. It gets more oxygen on the top. So, make sure to rectify the situation soon, or else the fish in the tank will start dying.

Can black skirt tetras live together with angelfish?

The black tetras and angelfish can comfortably stay in the same tank with ample space for free movements. However, there are a few instances where the black tetras have started nipping the fins of angelfish.

Now, this usually happens when there are very few tetras for interaction. So, to protect angelfish’s fins, you can put some extra fish of black tetra variety.

Takeaway – Why Should You get the Black Tetras at Home?

Black Skirt Tetras are ideal fishes to pet at home since they display stunning beauty with magical colors and come in cute small sizes that can fit in small tanks too.

These fishes capture a set market, so first-time breeders looking for some commercial opportunity can opt for these as they are easy to breed.

Even if purchased for home decoration in aquariums, these are suitable choices, but it is better to buy them in groups.

These fishes are comfortable with other varieties, so you do not have to look for another separate tank. (Avoid keeping long-finned fishes such as Goldfish)

About the Author

Victoria Lamb

Victoria is a freshwater aquatics specialist, fish keeper, and amphibian enthusiast. She has had more than 6 years of experience caring for aquariums and keeping several fish species, and her home boasts of 3 aquariums and a garden pond. Her goal is to educate fish owners on raising healthy and happy aquatic pets.

Career Highlights:

  • Has worked with several aquarium manufacturers as a consultant
  • Organized and hosted workshops on freshwater fish keeping at retail stores, educational facilities, and libraries
  • Released content for the amphibian community through her writings

Educational Highlights:

Bachelor of Science in Animal Behavior and Welfare

  • University of Lincoln, Lincoln, UK (2014-2018)

Writing Experience

Victoria has done ghostwriting for many aquarium and pet websites in the past. She has also worked for Canada's largest natural health magazine- ALIVE, with 300,000 monthly circulations as a freelancer. She had six published articles on animal behavior and welfare during her graduation for her thesis.

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