The Longfin Black Tetra (Gymnocorymbus ternetzi “longfin” variant) is a stunning variation of the popular Black Skirt Tetra, prized for its dramatic, flowing fins and sleek jet-black body. At around 3cm, this young fish displays the elegant fin extensions that give it a graceful presence in any freshwater aquarium. Known for its peaceful temperament and active schooling behavior, the Longfin Black Tetra is an excellent addition to community tanks, especially those with plants and moderate lighting where its fins can shimmer beautifully.

🐠 Key Features:

• Scientific Name: Gymnocorymbus ternetzi (longfin variant)

• Common Names: Longfin Black Tetra, Black Skirt Tetra (Longfin)

• Size: 3cm (juvenile; adults up to 6–7cm)

• Lifespan: 4–6 years

• Temperament: Peaceful, social

• Difficulty Level: Easy

• Origin: South America (Amazon basin, cultivated variants)

• Best kept in groups of 6 or more

🌊 Water Conditions

Longfin Black Tetras are adaptable and thrive in a range of freshwater parameters but prefer stable, moderate conditions:

• Temperature: 22–28°C (72–82°F)

• pH: 6.0–7.5

• Hardness: 4–15 dGH

• Tank Size: Minimum 20 gallons for a school

• Water Type: Freshwater

• Filtration: Moderate flow preferred

• Lighting: Moderate to dim, which accentuates their black coloration

A planted tank with open swimming space and some hiding spots is ideal to reduce stress and promote natural behavior.

🐟 Tank Mates

Known for their peaceful nature, Longfin Black Tetras do well in community tanks with other calm, medium-sized fish.

Compatible tank mates include:

• Other peaceful tetras (e.g., Neon, Cardinal)

• Corydoras catfish

• Rasboras

• Gouramis (peaceful species)

• Plecos (small species)

• Livebearers like guppies or platies

Avoid:

• Aggressive or fin-nipping fish

• Very small fish that may be mistaken as food

Keeping them in groups of 6 or more encourages schooling and reduces shyness.

🍽️ Feeding Habits

Longfin Black Tetras are omnivores and thrive on a varied diet:

• High-quality flake or pellet food

• Live or frozen foods such as bloodworms, brine shrimp, or daphnia

• Freeze-dried options (crushed)

• Occasional vegetable flakes or spirulina

Feed 1–2 times daily, offering only what they can consume in 2 minutes to avoid water pollution.

🧼 Care and Maintenance

• Weekly water changes of 25% help maintain water quality

• Stable water parameters prevent stress and disease

• Use gentle filtration to avoid fin damage

• Secure lid required—these active fish may jump

• Monitor for fin rot or injuries, especially on long fins

They are generally hardy and adapt well when provided a stable environment.

🌿 Why Choose the Longfin Black Tetra?

With its elegant flowing fins and striking black coloration, the Longfin Black Tetra adds sophistication and movement to any freshwater community tank. Its peaceful nature and easy care requirements make it perfect for both novice and experienced aquarists looking to enhance their aquarium’s visual appeal.

Bring home the graceful Longfin Black Tetra and elevate your aquarium’s elegance today!