Peruvian Red Pencilfish

The Peruvian Red Pencilfish (Nannostomus rubrocaudatus) is a small, peaceful freshwater fish prized for its vivid red coloration and striking appearance. Here’s a quick overview if you’re considering adding them to your stock or tanks:

🐟 Basic Info

• Scientific name: Nannostomus rubrocaudatus

• Common names: Peruvian Red Pencilfish, Ruby Red Pencilfish

• Origin: Peru, specifically the upper Amazon Basin

• Size: Up to 1.5 inches (around 4 cm)

• Lifespan: 3–5 years in good conditions

💧 Tank Requirements

• Tank size: Minimum 10 gallons for a small group

• Temperature: 74–82°F (23–28°C)

• pH: 5.5–7.0 (prefers soft, acidic water)

• Hardness: Low to moderate

• Lighting: Dim or subdued lighting helps them show off their colors

• Aquascape: Planted tanks with driftwood and leaf litter mimic their natural habitat well

🌿 Behavior & Compatibility

• Temperament: Peaceful, schooling fish; best kept in groups of 6 or more

• Tankmates: Great with other small, peaceful fish like rasboras, tetras, Corydoras, and dwarf shrimp

• Behavioral notes: Males may show subtle territorial displays but are generally not aggressive

🍽️ Diet

• Omnivorous: Eats high-quality flake food, micro pellets, frozen and live foods (like baby brine shrimp, daphnia)

🎨 Why They're Popular

• Their intense ruby red coloration with subtle horizontal striping makes them a striking addition to planted tanks.

• They're a relatively rare species in the hobby compared to other pencilfish.