Barred Pencilfish
Nannostomus sp.
Barred Pencilfish (Nannostomus sp.) — Varies care, Peaceful, under Other. Minimum tank in the app: 14.5 US gal min; aim for 72–82°F and pH 6.5–7.5. Barred Pencilfish are a charming choice for aquarists looking to enhance mid-water activity in a community setup, thanks to their unique swimming style and vibrant appearance.

Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
South America
- South America
Regional colours match the stocking calculator’s origin map.
Barred Pencilfish Tank Setup
Create a balanced environment with areas of open swimming space complemented by dense plant cover to facilitate their mid-water dynamics. Use fine substrate to prevent injury and ensure gentle filtration to minimize stress from water movement. Lighting should be moderate, allowing them to feel secure while still showcasing their colour.
What Do Barred Pencilfishs Eat?
Barred Pencilfish are generally moderate feeders, comfortably adapting to a variety of foods. Watch for competition during feeding times, as faster or more assertive species can outcompete them, potentially leading to nutritional deficiencies.
Barred Pencilfish Tank Mates
Ideal companions include small, non-aggressive species that occupy different swimming zones, such as tetras or rasboras. Avoid larger, boisterous fish that may intimidate them or compete for space. While they don’t shoal, keeping them in small groups can enhance their comfort; however, ensure no aggressive tendencies arise during social interactions.
Are Barred Pencilfishs Good for Beginners?
Care demand varies with setup and individual fish; use the numbers above as your baseline. Aquarists often underestimate the importance of tank structure and may provide inadequate cover, leading to stress and territorial disputes. overstocking or mixing with overly aggressive species can result in heightened stress and potential aggression, adversely affecting their well-being.
Building a community? Run the full list through the stocking calculator before you add anything else.
Log tests and reminders in App-aquatic—free, same data you see here.




