Junior Tetra

The Junior Tetra, scientifically known as Hyphessobrycon robustulus, is a small, lesser-known species of tetra native to the Amazon Basin in South America. It inhabits slow-moving tributaries and flooded forest areas where soft, acidic water and dense aquatic vegetation are common. Although not widely seen in the aquarium trade, it is occasionally collected and appreciated for its peaceful nature and compatibility with other small, community fish.

Adult Junior Tetras typically reach about 1 to 1.2 inches (2.5 to 3 cm) in length. They have a delicate, semi-transparent body with a slight silvery-gold sheen. The fins, especially in males, often display subtle reddish or orange hues, while females are generally more subdued in coloration. Their subtle beauty and calm schooling behavior make them ideal for planted aquariums and blackwater setups.

A tank of at least 10 to 15 gallons is sufficient for a small group. Like most tetras, they should be kept in groups of six or more to reduce stress and encourage natural shoaling behavior. The aquarium should include fine-leaved plants, driftwood, and leaf litter to provide cover and mimic their natural environment. Dim lighting or the use of floating plants will help them feel secure and bring out their coloration.

Water parameters should include a temperature of 74 to 82°F (23 to 28°C), a pH between 5.5 and 7.0, and soft to moderately hard water. They are sensitive to poor water quality, so regular maintenance and gentle filtration are important.

Feeding Hyphessobrycon robustulus is easy, as they accept a wide range of small foods. Offer high-quality micro pellets, crushed flakes, and live or frozen fare like daphnia, baby brine shrimp, or cyclops. Their small mouths require fine food particles.

They are peaceful and do well with similarly sized fish like small rasboras, pencilfish, pygmy Corydoras, and dwarf cichlids. Avoid keeping them with larger or boisterous species.

Breeding in captivity is possible but rarely attempted. They are typical egg-scattering tetras with no parental care. A separate breeding tank with soft, acidic water, spawning mops, and dense plants can help induce spawning. Adults should be removed after eggs are laid.

Hyphessobrycon robustulus (Junior Tetra) is a peaceful, attractive nano species that adds subtle beauty and schooling motion to softwater community or biotope aquariums.