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Species Spotlight: Black Skirt Tetra (Gymnocorymbus Ternetzi)

Home > Library > Species Spotlight > Aquatic > Freshwater Aquarium > Freshwater Fish > Characidae Family > Black Skirt Tetra (Gymnocorymbus Ternetzi)

Species Overview and Background:

  • Scientific Name: Gymnocorymbus Ternetzi
  • Common Names: Black Skirt Tetra, Black Widow Tetra, Petticoat Tetra
  • Temperament: Peaceful
  • Care Level: Beginner
  • Life Span: 5-8 years

  • The Black Skirt Tetra (Gymnocorymbus Ternetzi) was first discovered in the 19th century by a German naturalist named Franz Steindachner. The exact location of its discovery is uncertain, but it is believed to have been found in South America, specifically in the Paraguay and Guaporé River basins.
  • In its natural habitat, the Black Skirt Tetra can be found in slow-moving rivers, streams, and flooded areas. It typically inhabits densely vegetated areas with submerged vegetation and overhanging plants, providing ample hiding spots and shelter. It is often found in large groups and may coexist with other individuals of the same species.
  • Black Skirt Tetras are omnivorous in nature and feed on a variety of food sources. In the wild, they actively consume small insects, insect larvae, crustaceans, plant matter, and algae. Their diet consists of both animal and plant-based foods.
  • The natural behaviour of Black Skirt Tetras is generally peaceful, although they can sometimes exhibit mild aggression during feeding or when establishing territories. They are known to be shoaling fish, preferring to live in large groups. Being in a group helps to reduce stress and provides a sense of security for these fish.
  • The Black Skirt Tetra was introduced to the aquarium hobby in the early 20th century, and since then, it has gained popularity among hobbyists due to its striking appearance and relatively easy-care requirements. It’s contrasting black coloration and active swimming behaviour make it an attractive addition to aquariums.
  • Black Skirt Tetras have become quite famous in the aquarium hobby due to their eye-catching appearance and ease of care. Their black coloration, contrasting with the bright colours of other fish or aquarium decorations, adds visual interest to the tank. Additionally, their peaceful nature makes them compatible with a wide range of tank mates.
  • They are relatively common in the hobby and their popularity and availability make them easily accessible for both beginner and experienced aquarium keepers.
  • The ideal minimum group size for Black Skirt Tetras in a tank is six individuals or more. Keeping them in larger groups helps mimic their natural behaviour, reduces stress, and encourages their social interactions. For a group of six Black Skirt Tetras, a tank size of at least 75 liters (20 gallons) is recommended.

General Water Parameters:

  • pH Range: 6.0-8.0
  • Temperature Range: 22-26°C (72-79°F)
  • GH Range: 4-12 dGH
  • KH Range: 4-8 dKH
  • TDS Range: 150-300 ppm

Colour & Appearance:

In terms of size, Black Skirt Tetras typically grow to a maximum length of about 7 centimetres (2.8 inches). The Black Skirt Tetra has a distinctive appearance that adds a touch of elegance to any aquarium. They have an elongated, slightly laterally compressed body shape. A prominent black stripe runs horizontally along the midline of their body, extending from the nose to the caudal fin. The fins of the Black Skirt Tetra can vary from black to translucent, depending on the individual. The coloration of this species is primarily black, hence the common name "Black Skirt Tetra." However, there are variations in colour. The primary body coloration is black, which gives them their common name. However, there can be variations in the intensity of black coloration among individuals. Some may display a solid black body, while others may have a more translucent or greyish appearance.

Care and Requirements:

  • Black Skirt Tetras are relatively low-maintenance fish, making them suitable for beginners. They are hardy and can adapt to a wide range of water conditions. However, providing them with optimal care will ensure their well-being and vibrant colours.
  • They are not demanding in terms of water parameters, but it is important to maintain stable conditions. Regular water testing and quality maintenance are crucial. Keeping the water clean and well-filtered is essential for their overall health.
  • Black Skirt Tetras are diurnal and active during the day. They are generally peaceful and can coexist with a variety of other peaceful community fish species. However, it is best to avoid keeping them with fin-nipping or aggressive fish that may harass or stress them.
  • While they do not spend all their time hiding, Black Skirt Tetras appreciate the presence of plants and other hiding spots in the aquarium. Providing them with ample vegetation, such as floating plants, dense aquatic plants, and driftwood, helps create a natural and secure environment for them. Additionally, providing hiding places will also encourage natural behaviours and reduce stress.
  • They are known to be mid-level swimmers, utilizing the middle and bottom areas of the tank. Therefore, providing a tank with ample horizontal swimming space is important. A well-decorated aquarium with open swimming areas and areas for exploration will ensure their comfort and natural behaviour.

Diet:

Black Skirt Tetras are omnivorous and have a relatively adaptable diet. In the wild, they feed on small insects, insect larvae, crustaceans, plant matter, and algae. In the aquarium, they readily accept a variety of commercially available fish foods, including high-quality flakes, pellets, and granules. It is recommended to provide a balanced diet consisting of both dry and frozen foods to ensure their nutritional needs are met.

Feeding behaviour: Black Skirt Tetras are active feeders and will eagerly swim to the surface to feed. They have a voracious appetite and should be fed small, frequent meals throughout the day. Offering a combination of flake or pellet foods and occasional live or frozen foods like bloodworms, brine shrimp, or daphnia will provide them with a varied and nutritious diet.

Tank Setup:

  • The minimum recommended tank size for a group of six Black Skirt Tetras is 75 litres (20 gallons). However, providing a larger tank will allow for a more spacious and natural swimming environment. A tank size of 113 litres (30 gallons) or more is ideal for a larger group.
  • Substrate: Black Skirt Tetras are not particularly picky about the type of substrate. They can be kept on fine gravel, sand, or a substrate specifically designed for aquarium use. The choice of substrate depends on personal preference and the overall aesthetic of the tank.
  • Plants: Adding live plants to the aquarium is highly beneficial for Black Skirt Tetras. They appreciate the presence of dense vegetation, which provides hiding spots and a sense of security. Suitable plant species include Java Fern, Anubias, Amazon Sword, Hornwort, and Vallisneria. These plants not only enhance the visual appeal of the tank but also help maintain water quality by absorbing nitrates and providing oxygen.
  • Decorations: Incorporating driftwood, rocks, and caves into the tank setup can provide additional hiding places and create a more natural environment. Black Skirt Tetras appreciate having retreats and shaded areas to retreat to when they feel the need for security. It is important to ensure that any decorations are aquarium-safe and do not contain sharp edges or toxic materials.
  • Water Flow and Filtration: Black Skirt Tetras do not have specific requirements regarding water flow. However, providing moderate water movement with the help of a filter or air stone can help maintain good water circulation and oxygenation. A hang-on-back (HOB) filter or sponge filter is generally sufficient for their needs. It is essential to choose a filter that is appropriately sized for the tank to maintain clean water conditions.
  • Lighting: Black Skirt Tetras do not have specific lighting requirements. They can adapt well to a range of lighting intensities, but it is recommended to provide moderate lighting levels to support plant growth and showcase their colours. The use of LED lights with adjustable brightness settings is a popular choice among aquarists.
  • Water Parameters: Maintaining stable water parameters is crucial for the health and well-being of Black Skirt Tetras. As previously mentioned, they can tolerate a wide range of water conditions, but consistency is key. Regular water testing and monitoring are necessary to ensure the following parameters remain within the recommended ranges:
    • pH: 6.0-8.0
    • Temperature: 22-26°C (72-79°F)
    • GH: 4-12 dGH
    • KH: 4-8 dKH
    • TDS: 150-300 ppm
  • Water Changes: Regular water changes are important to maintain good water quality and remove accumulated toxins. It is recommended to perform weekly partial water changes of around 20-30% to keep the water parameters stable and provide a healthy environment for the Black Skirt Tetras.

Compatibility and Ideal Tank Mates:

  • Black Skirt Tetras are generally peaceful and can coexist with a wide variety of peaceful community fish species. However, it is important to choose tank mates that share similar water parameter requirements and have compatible temperaments. Some suitable tank mates for Black Skirt Tetras include:
    • Tetras (such as Neon Tetras, Cardinal Tetras, and Harlequin Rasboras)
    • Corydoras Catfish
    • Dwarf Gouramis
    • Livebearers (such as Guppies, Platies, and Swordtails)
    • Small peaceful Rasboras (such as Chili Rasboras and Galaxy Rasboras)
    • Otocinclus Catfish
    • Plecos (such as Bristlenose Plecos)

It is important to avoid keeping them with fin-nipping or aggressive fish species, as this can lead to stress and potential damage to their fins. Additionally, large and aggressive fish should be avoided as they may intimidate or prey on the smaller Black Skirt Tetras.

Sexing:

Distinguishing between male and female Black Skirt Tetras can be challenging, especially when they are not in breeding condition. However, there are a few subtle differences that can help determine their sex:

  • Size and Body Shape: Male Black Skirt Tetras tend to be slightly smaller and slimmer than females. Females, especially when mature and ready to spawn, may have a rounder and more pronounced belly.
  • Anal Fin: In mature males, the anal fin is typically longer and more pointed compared to females. Female Black Skirt Tetras have a shorter and more rounded anal fin.
  • Coloration: During breeding, males may exhibit more intense black coloration and develop elongated, flowing fin extensions. Females, on the other hand, may have a slightly duller black coloration and lack the prominent fin extensions.

It is important to note that these differences may not be easily noticeable in all individuals, especially when they are not in breeding condition. Therefore, sexing Black Skirt Tetras with certainty can be challenging without the presence of distinct breeding characteristics.

Breeding:

Black Skirt Tetras can be bred in a well-maintained aquarium with suitable conditions. To encourage breeding, the following steps can be taken:

  1. Breeding Tank: Set up a separate breeding tank with a capacity of at least 38 litres (10 gallons). Provide ample hiding spots, such as dense vegetation, spawning mops, or fine-leaved plants, where the fish can deposit their eggs.
  2. Conditioning: Separate a group of sexually mature males and females into the breeding tank. Provide them with a high-quality and varied diet to ensure they are in optimal breeding conditions. Conditioning them with live or frozen foods, such as bloodworms and brine shrimp, can help stimulate spawning behaviour.
  3. Spawning Behaviour: When the conditions are suitable, the males will begin to chase and display courtship behaviours towards the females. The males may exhibit more intense coloration and extended finnage during this time. The female will release her eggs, and the male will fertilize them.
  4. Adult Removal: After spawning, the adults may consume the eggs. To maximize the survival rate of the fry, it is recommended to remove the adults from the breeding tank once spawning has occurred. The eggs are usually adhesive and will attach to the chosen substrate or plants.
  5. Hatching and Fry Care: The eggs typically hatch within 24 to 48 hours. The fry are initially very small and delicate. They can be fed commercially available liquid fry food or infusoria until they are large enough to accept finely crushed flake or powdered fry food.
  6. Water Parameters: Maintain stable and clean water conditions in the breeding tank. Frequent partial water changes and careful monitoring of water parameters are essential for the health and development of the fry.

It is important to note that not all Black Skirt Tetras will breed readily in a home aquarium. Providing suitable conditions, a proper diet, and separating a dedicated breeding pair or group can increase the chances of successful breeding.

Additional Considerations:

  • Black Skirt Tetras are generally hardy and relatively easy to care for, making them suitable for beginners. However, it is essential to maintain optimal water quality, provide a balanced diet, and ensure appropriate tank mates to promote their well-being.
  • Regular observation and monitoring of their behaviour, appetite, and overall health are recommended to identify any signs of stress, disease, or aggression. Prompt action should be taken if any issues arise, such as adjusting water parameters, providing appropriate medication, or separating aggressive individuals.
  • It is worth noting that Black Skirt Tetras have been selectively bred to enhance their black coloration and finnage. As a result, some commercially available specimens may exhibit exaggerated features. It is always advisable to obtain fish from reputable sources and avoid specimens with compromised health or exaggerated physical traits.

Lastly, when introducing Black Skirt Tetras to a new tank, it is important to acclimate them slowly and allow them time to adjust to their new environment. This can be done by floating the bag containing the fish in the aquarium for about 15-20 minutes to equalize the temperature. Afterward, gradually add small amounts of aquarium water to the bag at regular intervals over the course of about 30 minutes. This will help them acclimate to the water chemistry of the tank. Finally, carefully release the Black Skirt Tetras into the aquarium, ensuring they are not stressed or harassed by other tank mates.

In summary, the Black Skirt Tetra (Gymnocorymbus ternetzi) is a popular and attractive species in the aquarium hobby. Their black coloration, active behaviour, and peaceful temperament make them an excellent addition to community aquariums. With proper care, a suitable tank setup, and a balanced diet, these tetras can thrive and exhibit their vibrant colours. They are relatively hardy and adaptable, making them suitable for beginners and experienced hobbyists alike.

Remember to maintain stable water conditions, provide hiding spots and vegetation, and choose compatible tank mates. Regular monitoring of water parameters and observation of their behaviour will help ensure their well-being. With the right care and attention, Black Skirt Tetras can provide years of enjoyment in the aquarium hobby. Enjoy the beauty and grace of these fascinating fish in your aquarium!