The Purple Pencilfish, scientifically known as Nannostomus rubrocaudatus, is a stunning and relatively rare species of freshwater fish native to the blackwater streams and tributaries of the Amazon Basin in South America. This species is highly prized by aquarists for its striking coloration, peaceful nature, and unique behavior, making it a delightful addition to well-maintained aquariums.

Purple Pencilfish are characterized by their slender, elongated bodies and vibrant coloration. Their bodies are primarily a shimmering purplish or reddish hue, with a distinctive black horizontal stripe running from the snout to the tail. The tail fin is usually marked with bright red or orange, adding to their overall visual appeal. Their dorsal and anal fins are often highlighted with white or light-colored edges, which contrast beautifully with the rest of their body.

In captivity, Purple Pencilfish thrive in aquariums that closely mimic their natural blackwater habitat. A tank setup should include plenty of live plants, such as Java moss, Anubias, and floating plants, which provide cover and help replicate the subdued lighting conditions of their native environment. A dark substrate and the addition of driftwood and leaf litter can help create the tannin-rich water conditions that these fish prefer.

Water conditions should be soft and slightly acidic, reflecting the blackwater streams they originate from. Maintaining stable water parameters through regular water changes and efficient filtration is crucial for the health and well-being of Purple Pencilfish. They are sensitive to poor water quality and fluctuations in water conditions, so consistency is key.

Purple Pencilfish are peaceful and social fish that should be kept in groups of at least six or more to promote their well-being and natural schooling behavior. Keeping them in a school not only reduces stress but also enhances their vibrant colors and active swimming patterns. They are excellent community fish and can be housed with other small, non-aggressive species that thrive in similar water conditions.

Their diet should be varied to ensure they receive all the necessary nutrients. Purple Pencilfish are omnivorous and will readily accept high-quality flake foods, micro pellets, and live or frozen foods such as brine shrimp, daphnia, and bloodworms. Providing a mix of these foods will help maintain their health, vibrant colors, and energetic behavior.

Breeding Purple Pencilfish in captivity can be challenging due to their specific environmental needs. They are egg scatterers, typically laying their eggs among fine-leaved plants. To encourage breeding, maintain optimal water conditions with soft, slightly acidic water and provide plenty of fine-leaved plants or spawning mops. Once spawning occurs, it is advisable to remove the adults from the breeding tank to prevent them from eating the eggs. The eggs usually hatch within a few days, and the fry can be fed with infusoria or finely crushed flake food until they are large enough to accept standard fare.

Overall, the Purple Pencilfish is an excellent choice for aquarists looking for a small, colorful, and peaceful species. Their striking appearance, gentle nature, and dynamic behavior make them a delightful addition to any well-maintained aquarium. With proper care and the right environment, they can thrive and bring a touch of vibrant beauty and lively activity to your aquatic setup.