Black Morpho Tetra / Poecilocharax weitzmani (10 Count)

Common Name: Black Morpho Tetra
Scientific Name: Poecilocharax weitzmani
Other Names: Weitzman’s Tetra, Black Darter Tetra

The Black Morpho Tetra is a rare and striking freshwater fish known for its elongated body, deep black coloration, and unique iridescent blue sheen that resembles the wings of a Morpho butterfly. It is a highly sought-after species due to its rarity in the aquarium trade and its fascinating behavior.

Habitat and Distribution: Poecilocharax weitzmani is native to the clear, slow-moving blackwater streams and tributaries of the Rio Negro and Orinoco River basins in South America. These waters are rich in tannins from decomposing leaf litter, creating soft, acidic conditions with low mineral content. The fish prefer environments with dense aquatic vegetation, submerged branches, and leaf litter, where they can find shelter and forage for small invertebrates.

Size and Lifespan: Black Morpho Tetras are relatively small, reaching around 1.5-2 inches (4-5 cm) in length. Despite their size, they can live 3-5 years with proper care in a well-maintained aquarium.

Diet and Behavior: These tetras are micro-predators, feeding primarily on small invertebrates, insect larvae, and zooplankton in the wild. In an aquarium, they should be fed a varied diet that includes:

• Live or frozen foods such as baby brine shrimp, daphnia, bloodworms, and cyclops
• High-quality micro pellets or crushed flakes
• Occasionally blanched vegetables like spinach or zucchini

They are generally peaceful but can be shy and reclusive, preferring to stay close to the bottom or among plant cover. They do best in small groups of 6 or more, where they exhibit more natural behaviors and feel secure. Unlike many other tetras, they display darter-like movements, occasionally perching on leaves or the substrate.

Breeding and Reproduction: Breeding Black Morpho Tetras in captivity is difficult and has only been successfully achieved by advanced aquarists. They are egg scatterers, depositing their eggs among fine-leaved plants or in secluded areas. The male may display territorial behavior, guarding a chosen area where spawning takes place. To encourage breeding:

• Provide soft, acidic water (pH 4.5-6.0)
• Use leaf litter and dense plants to create spawning areas
• Feed a protein-rich diet to condition the breeding pair
  After spawning, adults should be removed, as they may consume their own eggs. The fry are extremely tiny and require microscopic food like infusoria before transitioning to baby brine shrimp.

Aquarium Care and Tank Requirements: Black Morpho Tetras require a biotope-style setup to mimic their natural blackwater habitat. A minimum of 20 gallons is recommended for a small group. Their ideal tank setup includes:

• Substrate: Soft sand or fine gravel with leaf litter to release tannins
• Decor: Driftwood, caves, and floating plants for shade and security
• Filtration: A sponge filter or gentle flow to replicate their calm environment
• Lighting: Dim or subdued lighting to enhance their colors and reduce stress
• Water Quality: Frequent water changes are necessary, as they are sensitive to fluctuations

Ideal Tank Mates: Due to their small size and peaceful nature, Black Morpho Tetras should be housed with other peaceful, small fish that thrive in soft, acidic water. Suitable tank mates include:

• Other blackwater tetras (such as Ember or Cardinal Tetras)
• Small Rasboras (like Chili or Phoenix Rasboras)
• Dwarf Cichlids (such as Apistogramma or Dicrossus species)
• Otocinclus Catfish
• Avoid larger or aggressive species that may intimidate or outcompete them for food.

Difficulty Level: Advanced. These tetras require stable water parameters, a blackwater setup, and a diet consisting primarily of live or frozen foods. Their sensitive nature makes them best suited for experienced aquarists.

Water Parameters:

• Temperature: 75-82°F (24-28°C)
• pH: 4.5-6.5 (preferably acidic)
• General Hardness (GH): 1-6 dGH (very soft water)
• Carbonate Hardness (KH): 1-4 dKH
• Ammonia: 0 ppm
• Nitrite: 0 ppm
• Nitrate: <10 ppm (sensitive to water quality issues)

Additional Information: Black Morpho Tetras are one of the most enigmatic and beautiful nano fish in the aquarium trade. Their deep black body with a blue iridescent shimmer makes them highly desirable, but their specific care requirements and difficulty in sourcing make them a rare addition. Fun fact: Unlike most tetras, they have a unique darter-like swimming behavior, occasionally perching on plants and rocks, making them a fascinating species to observe in a naturalistic setup.