Black Skirt Tetra 
© Danykur / stock.adobe.com
Mourning cloak tetras are peaceful and extremely popular aquarium fish.
A robust, easy-to-keep, and attractive addition: the black skirt tetra is particularly popular with aquarium newbies. Discover what makes these fish so special in this comprehensive profile.
Table of contents
- What does the black skirt tetra look like?
- Behaviour: Peaceful & undemanding aquarium inhabitants
- Proper care for black skirt tetras
- Nutrition: What do black skirt tetras eat?
- Health: How long do black skirt tetras live?
- Breeding: How do black skirt tetras reproduce?
- The natural habitat of the tetras
- Purchase: What is the cost of a black skirt tetra?
What does the black skirt tetra look like?
The black skirt tetra (Gymnocorymbus ternetzi) is a freshwater ornamental fish that reaches a maximum size of 5.5 centimeters. Its anal fins resemble a dark cloak, earning it its distinctive name. The fish has a slim and high-backed body.
What colours are available?
The wild type has a silver base colour, which fades with age. However, there are bred varieties that exhibit other colour variations and fin shapes.
At the rear and on the anal, adipose, and dorsal fins, the fish is black. It also has two dark vertical stripes at the front.
Note: There are also cultivated forms with a pink-gold colour (albino black skirt tetras) or longer fins (veil black skirt tetras).
Differences between females and males
You can determine the sex by two characteristics. On the one hand, the sturdier females usually grow larger (up to five centimeters) than the males.
The dorsal fin of the male is also generally a bit more pointed than that of the female.
Behaviour: Peaceful & undemanding aquarium inhabitants
Black skirt tetras are known to be strong swimmers who enjoy activity. They are also peaceful towards other fish – rarely are there any fights.
Like other tetras (such as silvertip tetras, neon tetras), black skirt tetras live a shoaling existence. This means that these fish live in groups of at least ten individuals.
Which fish can be kept with black skirt tetras?
Black skirt tetras meet all the requirements to cohabit with other peaceful fish in a community aquarium.
From discus, catfish, and dwarf cichlids to barbs, guppies, and other tetra species – the black skirt tetra gets along with a variety of fish species.
Caution: However, be wary with young shrimp, as they may be eaten by the fish.
Proper care for black skirt tetras
As an easy-to-care-for fish, black skirt tetras are very suitable for beginners opting for a community aquarium. However, individual requirements of this fish species should be considered to ensure your fish remain happy and healthy long term.
Size of the aquarium
To ensure your active swimmers have enough space, the aquarium should have a minimum capacity of 112 litres. An 80 centimeters length is recommended.
Ideal water values
Black skirt tetras are generally robust when it comes to water hardness in the aquarium.
The following water values should be maintained in the aquarium:
- Water hardness: ideally up to 10° dGH, 5 to 20° dGH possible
- pH value: 6 to 8
- Temperature: 20 to 28 °C
Planting and substrate
Black skirt tetras love hiding places, so the aquarium should have some areas with dense but loose planting. Plant some floating plants to protect your shade-loving fish from bright light.
Dark substrate is suitable as a substrate.
Nutrition: What do black skirt tetras eat?
As omnivores, your black skirt tetras can be fed with conventional dry food for tetras.
To add some variety to their diet, you can offer your fish live or frozen food (such as brine shrimp, mosquito larvae, saltwater shrimp) once or twice a week.
Health: How long do black skirt tetras live?
The average lifespan of this species of tetra in the wild is about one to two and a half years. In captivity, black skirt tetras generally live longer, usually between six and ten years.
How robust are black skirt tetras?
Although these popular fish are fundamentally very robust and can withstand fluctuations in water quality to some extent, they can suffer from typical fish diseases. These primarily include:
- Fish tuberculosis
- Fin rot
- Neon tetra disease
- Fungal infections (such as fish fungus)
- Velvet disease
Breeding: How do black skirt tetras reproduce?
If you wish to breed offspring, you will need a spawning tank with a capacity of about 30 litres. Equip the tank with java moss and set the following values: temperature at 24 to 28 °C and water hardness below 10° dGH.
Place at least one pair into this tank. As scatter spawners, black skirt tetras do not care for their brood and lay sperm and eggs in open water (or on plant parts), which can involve up to 500 eggs.
From spawning to rearing
Since black skirt tetras are egg-scavengers, you must definitely transfer the parents back to the regular aquarium after spawning.
After a few days, the eggs hatch. After five days, the yolk sac is consumed, so you should then start feeding freshly hatched brine shrimp nauplii. After that, powdered food is suitable.
The natural habitat of the tetras
In the wild, black skirt tetras are found in the rivers of South America, particularly in Argentina, Bolivia, and Paraguay.
They generally prefer the slow-flowing and shaded waters of the Rio Guapore, Rio Paraguay, and Rio Parana.
© juancajuarez / stock.adobe.com
Purchase: What is the cost of a black skirt tetra?
Due to their popularity, these fish species can be found in every well-stocked pet shop with an aquarium section.
Expect to pay about two to four euros per individual.
Fact Sheet on Black Skirt Tetras
| Name: | Black Skirt Tetra (Gymnocorymbus ternetzi) |
| Body length: | a maximum of 5.5 cm |
| Lifespan: | up to 12 years |
| Keeping: | Group keeping (more than 10 animals) |
| Compatibility: | possible with many fish species |
| Aquarium: | Community tank |
| Water temperature: | 20 to 28 °C |
| Water values: | pH value 6.0 to 8, 5 to 10° dGH |
| Food: | Dry and live food |
| Difficulty level: | easy |
At the Justus-Liebig-University of Giessen I was extensively trained as a veterinarian and was able to gain experience in various fields such as small animal, large animal and exotic animal medicine as well as pharmacology, pathology and food hygiene. Since then, I have been working not only as a veterinary author, but also on my scientifically driven dissertation. My goal is to better protect animals from pathogenic bacterial organisms in the future. Besides my veterinary knowledge, I also share my own experiences as a happy dog owner and can thus understand and enlighten fears and problems as well as other important questions about animal health.
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