The Purple Pencilfish (Nannostomus mortenthaleri “Purple” or similar variants) is a small, peaceful freshwater species prized for its iridescent purple-red coloration and slender, pencil-like body. Native to slow-moving streams and blackwater habitats in South America, they thrive in planted aquariums with soft, acidic water, gentle filtration, and subdued lighting that mimics their natural environment. These schooling fish should be kept in groups of at least 6 to display natural behavior and reduce stress. Their omnivorous diet includes high-quality micro-pellets, finely crushed flakes, and live or frozen foods such as daphnia, brine shrimp, and micro-worms. They are sensitive to water quality, so regular water changes and stable conditions are essential. When properly cared for, Purple Pencilfish display vibrant coloration and active schooling behavior, making them an attractive addition to peaceful community tanks.
| Parameter | Requirement |
|---|---|
| Scientific Name | Nannostomus mortenthaleri (Purple Pencilfish variant) |
| Tank Size | Minimum 10 gallons |
| Temperature | 24–28°C (75–82°F) |
| pH Range | 5.5–7.0 |
| Water Hardness | Soft (1–8 dGH) |
| Substrate | Sand or fine gravel with dense plants and floating vegetation |
| Diet | Omnivorous – micro-pellets, finely crushed flakes, live/frozen daphnia, brine shrimp, micro-worms |
| Temperament | Peaceful, ideal for community tanks |
| Social Behavior | Schooling; best kept in groups of 6+ |
| Breeding | Egg scatterer; floating plants help fry survival |
| Lifespan | 3–5 years with proper care |
