Acestrorhamphidae

Black Skirt Tetra (Veiltail)

Gymnocorymbus ternetzi

A form of:Black Tetra

Gymnocorymbus ternetzi, more commonly known as the Long-finned Black Skirt Tetra, belongs to the Acestrorhamphidae family. This fish represents one of the morphological variations of the Black Skirt Tetra, distinguished by its elongated, flowing fins. Despite its artificial origin, this form is characterized by good hardiness, making it a suitable choice even for aquarists without extensive experience.

Tank
from 60 L (16 gal)
Temperature
22 – 26 °C (72 – 79 °F)
Size in aquarium
5 – 6 cm (2 – 2.4 in)
Acidity
pH 6–8
Natural rangeRange on the map
  • Paraguay River Basin
  • Guaporé River
  • Argentina
  • Bolivia
  • Brazil
  • Paraguay

Tank conditions

Plan the tank stocking
Temperature
22 – 26 °C (72 – 79 °F)
Water pH
Slightly acidic (6) – Slightly alkaline (8)
Water dH
Soft (5) – Very hard (19)
Water salinity
no salt (freshwater)
Size in aquarium
5 – 6 cm (2 – 2.4 in)
Lifespan
7 years
Temperament
Peaceful, but may bite fins
Toward small fish
not a predator
Required aquarium volume
from 60 L (16 gal)
Lighting
dimmed
Substrate
any (no restrictions)
Water flow
weak
Swimming level
middle level
Feeding
Any (universal)
Keeping
Schooling usually from 5–6 individuals and more
Jumping
high a tight-fitting lid is essential
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (schooling (usually from 5–6 individuals and more)), footprint, decor and tank mates.

Care and keeping

Description

The fish has a high body, flattened laterally. The fins are significantly larger compared to the original species and can reach a length comparable to the fish's own size. The body coloration and caudal fin are usually silvery, while the anal and dorsal fins are black, giving the fish an overall dark hue. Over time, the fins may acquire a gray tint. Two vertical bands are clearly visible on the body, which are a characteristic feature of this species.

Habitat

This species is not found in the natural environment, as it was artificially bred from the Black Skirt Tetra. The first successful results of selective breeding were achieved in Europe. Today, there are many diverse forms of this fish supplied to aquarium stores worldwide.

Behavior and Compatibility

This species is active and relatively peaceful. It is important to keep them in schools of at least 6 individuals. With such a number, all their attention will be focused on interaction within the group, whereas a smaller number of individuals can provoke aggression towards other species. Coexistence is permissible with fish of similar or slightly larger size. However, it should be remembered that some varieties are well-known for their "interest" in fish with elongated fins, and Tetras can, unfortunately, become their victims in the same aquarium.

Care and Maintenance

Thanks to their modest size, Long-finned Tetras can feel comfortable in aquariums with a volume of 60 L or more. To maintain consistently high water quality, an effective filtration system and regular partial water changes (25–50%) every two weeks are necessary. Lighting should be subdued, so low-power lamps are preferable. Essential equipment also includes a heater and an air pump. When decorating the aquarium, it is best to choose low-growing plants, planting them in groups along the side walls to leave enough open swimming space. Sandy substrate is recommended. Various artificial structures, such as castles, sunken ships, chests, as well as natural elements like bogwood, roots, or snags, can serve as shelters and decorative elements.

Diet

These fish readily accept all varieties of both dry commercial and live foods. An ideal diet for them includes high-quality flakes or granules, which should be offered up to three times a day.

Breeding and Reproduction

The Long-finned Black Skirt Tetra breeds easily in a home aquarium, with an enriched daily diet of meaty foods serving as a stimulus for spawning. Since these fish do not exhibit parental care for their offspring, a separate tank should be used for breeding. The spawning aquarium typically has a volume of 30–40 L. The recommended equipment includes a lighting system, a simple air-driven filter, and a heater. The decor must include low-growing leafy plants (artificial ones are acceptable), and the substrate should consist of coarse gravel about 1 cm in diameter. When an increase in the abdominal volume of one or more females becomes noticeable, this indicates approaching spawning. The female(s) or one female should be transferred to the spawning aquarium, and the male should be added the next day. Until egg laying, continued intensive feeding of the future parents with meaty products is necessary; this period can last up to a week or less, depending on individual gestation times. The female lays eggs in one or more places, after which the male fertilizes them. After spawning, the parents are returned to the main aquarium. Fry appear within a few days and soon begin to move freely. They should be fed micro-food or Artemia, and the lighting should be continuous, as fry have difficulty finding food in the dark.

Diseases

This species is highly hardy but extremely sensitive to water temperatures below the recommended level. In such conditions, problems with external coverings begin: fungus may appear, as well as infections by protozoa.

How to choose

When selecting individuals, pay attention to the fish's activity: healthy tetras are active, stay in a school, and do not show signs of apathy. It is important to carefully inspect the body for the absence of spots, ulcers, film, or fin damage, as veiltail forms are particularly susceptible to infections when stressed. Avoid buying fish with signs of emaciation or an unnaturally swollen abdomen. — choose individuals from aquariums where there are no dead fish; — assess the integrity of the fins, excluding specimens with signs of fraying or nipping; — check the coloration: in healthy fish, it is clear, without pale spots indicating poor keeping conditions.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Black Skirt Tetra (Veiltail) get?

An adult reaches 5–6 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Black Skirt Tetra (Veiltail) need?

The recommended volume is 60 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Black Skirt Tetra (Veiltail) need?

Temperature 22–26 °C, pH 6–8, hardness 5–19 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Black Skirt Tetra (Veiltail) live?

Around 7 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Black Skirt Tetra (Veiltail) aggressive?

Temperament: peaceful, but may bite fins. Keep this in mind when choosing tank mates.

How many Black Skirt Tetra (Veiltail) should be kept together?

Recommended setup: schooling (usually from 5–6 individuals and more). Ignoring this is a common cause of stress and disease.

What does Black Skirt Tetra (Veiltail) eat?

Diet type: any (universal). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Black Skirt Tetra (Veiltail)?

The scientific name of the species is Gymnocorymbus ternetzi, family Acestrorhamphidae. It also appears in the literature as: Gymnocothymbus ternetzii, Tetragonopterus ternetzi.

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Other scientific names and conservation status

Other scientific names
Gymnocothymbus ternetzii, Tetragonopterus ternetzi
Categories
Characins
Conservation status
Least concernLC