The Black Morpho Tetra is a dramatic and elegant freshwater fish that has become increasingly popular in home aquariums due to its deep black coloration, peaceful nature, and ease of care. Often confused with or grouped under the common Black Widow Tetra, the Black Morpho is a selectively bred color morph of Gymnocorymbus ternetzi, prized for its velvety dark body and subtle iridescence under aquarium lighting.
This species is an excellent choice for aquarists seeking contrast in planted community tanks. When kept in proper schools and suitable conditions, Black Morpho Tetras display confident behavior and striking visual appeal, making them a standout among South American characins.
Scientific Classification and Related Species
Latin Name and Family
Scientific Name: Gymnocorymbus ternetzi
Family: Characidae
The Black Morpho Tetra belongs to the same species as the well-known Black Widow Tetra. Other close relatives within the Characidae family include species such as the Diamond Tetra and the Redeye Tetra, all known for schooling behavior and community-friendly temperaments.
Is the Black Morpho Tetra a Natural Species?
No. The Black Morpho Tetra is not found in the wild. It is a selectively bred color morph developed from wild-type Gymnocorymbus ternetzi. Its jet-black coloration is enhanced through generations of captive breeding, though its care requirements remain identical to the natural form.
Natural Origin and Habitat
While the Black Morpho itself does not occur in nature, its parent species originates from South America, primarily in the Paraguay and Guaporé River basins of Brazil and Bolivia. In the wild, these fish inhabit slow-moving rivers, floodplains, and shaded forest streams rich in leaf litter and submerged vegetation.
This natural environment explains their preference for subdued lighting, gentle water flow, and aquariums that incorporate plants, driftwood, and darker substrates.
Physical Appearance and Size
Adult Size
Black Morpho Tetras typically reach an adult size of 5 to 6 cm (approximately 2 to 2.5 inches). Females are generally slightly larger and deeper-bodied than males.
Coloration and Fins
The defining feature of the Black Morpho Tetra is its deep black body coloration, often appearing matte or velvety. Under strong lighting, subtle silver or charcoal highlights may be visible. The fins are elongated and flowing, particularly the anal fin, which adds to their graceful swimming style.
Temperament and Community Tank Compatibility
Black Morpho Tetras are peaceful, social fish best kept in groups of at least six, though larger schools of ten or more are strongly recommended. When kept in insufficient numbers, they may become shy or exhibit mild fin-nipping behavior.
Good Tank Mates
These tetras do very well in community aquariums and coexist peacefully with many similarly sized species, including:
– Neon Tetras
– Harlequin Rasboras
– Bronze Corydoras
– Otocinclus Catfish
– Peaceful dwarf cichlids such as Apistogramma cacatuoides
Avoid housing them with aggressive or fin-nipping species, as their flowing fins can become targets.
Tank Size and Setup
Minimum Tank Size
A minimum tank size of 20 gallons is recommended for a small group, though larger aquariums provide better swimming space and more stable water parameters.
Aquascaping Preferences
Black Morpho Tetras thrive in well-planted aquariums. Background plants such as Vallisneria and midground plants like Cryptocoryne help recreate their natural environment. Floating plants can be used to diffuse light and reduce stress.
For guidance on creating an ideal setup, refer to Setting Up Your First Freshwater Aquarium.
Water Conditions
Ideal Parameters
Temperature: 22–26°C (72–79°F)
pH: 6.0–7.5
Hardness: Soft to moderately hard water
Stable water conditions are far more important than chasing exact numbers. Regular water changes and good filtration are essential for long-term health.
Diet and Feeding
Black Morpho Tetras are omnivorous and unfussy eaters. In the wild, they feed on small insects, crustaceans, and plant matter.
Recommended Foods
– High-quality tropical flakes or micro pellets
– Frozen or live foods such as bloodworms and daphnia
– Occasional vegetable-based foods
A varied diet enhances coloration, boosts immunity, and supports breeding readiness. Feeding small amounts two times daily is ideal.
Sexing Black Morpho Tetras
Sexing can be subtle but becomes easier as the fish mature. Females tend to be rounder, especially when carrying eggs, while males are slimmer with slightly more pointed fins.
Breeding the Black Morpho Tetra
Breeding is achievable for dedicated aquarists but requires preparation. A separate breeding tank with soft, slightly acidic water and fine-leaved plants or spawning mops is recommended.
Breeding Behavior
Condition the breeding pair with live foods. Spawning typically occurs early in the morning, with eggs scattered among plants. Adults should be removed immediately, as they may consume the eggs.
Eggs hatch within 24–36 hours, and fry become free-swimming after a few days. Infusoria or liquid fry food is necessary during the initial stages.
Ease of Care
The Black Morpho Tetra is considered an easy-to-moderate care fish, making it suitable for beginners with some basic aquarium knowledge. Their hardiness and adaptability make them forgiving of minor mistakes, provided water quality is maintained.
Species Variations and Albino Form
Color Variations
Besides the Black Morpho, Gymnocorymbus ternetzi is available in several forms, including the classic silver-and-black Black Widow Tetra and long-finned varieties.
Albino Black Widow Tetra
The Albino version lacks dark pigmentation and appears pale white to pinkish, often with red eyes. While visually striking, albino specimens can be more sensitive to bright lighting and require additional cover to feel secure. Care requirements otherwise remain identical.
Frequently Asked Questions
Are Black Morpho Tetras aggressive?
No, they are peaceful schooling fish. Minor fin-nipping can occur if kept in too-small groups.
How many Black Morpho Tetras should be kept together?
A minimum of six is recommended, but groups of ten or more display the best behavior and coloration.
Can Black Morpho Tetras live with shrimp?
They may coexist with larger shrimp species, but very small shrimp or shrimplets may be at risk.
Conclusion
The Black Morpho Tetra is an excellent addition to freshwater community aquariums, offering dramatic coloration without demanding care requirements. With proper schooling, stable water conditions, and a thoughtfully aquascaped environment, these fish reward aquarists with confident behavior and striking visual contrast. Whether you are a beginner or an experienced hobbyist, this refined tetra variety remains a timeless and reliable choice.
