One-lined Pencilfish
Nannostomus unifasciatus
Also known as: One-lined Pencilfish, Single-striped Pencilfish
Origin: South America (widespread Amazon basin)
Water Parameters
Quick Stats
- Max Size
- 6.5 cm
- Min Tank
- 60 L
- Lifespan
- 3-5
- Swimming Level
- middle
- Schooling
- Yes (6–12+)
- Diet
- omnivore
- Temperament
- peaceful schooling fish
About
Nannostomus unifasciatus, the One-lined Pencilfish, is widespread throughout the Amazon basin. Its clean, simple patterning — a single bold black stripe on a golden-silver body — has a refined elegance. At up to 6.5 cm it is larger than most pencilfish, lending itself to medium community aquariums. Like its relatives, it rests at an oblique angle when inactive.
Care Guide
Water: 24–28°C, pH 5.5–7.0, soft and slightly acidic. Tank: 60 L minimum; well-planted with gentle filtration; floating plants appreciated. Feeding: Accepts flake and micro-pellets; benefits from frozen brine shrimp and micro-worms. Behaviour: Peaceful schooling species; keep 8+; adopts distinctive oblique resting posture at night. Compatibility: Good with small peaceful tetras, corydoras, small rasboras and dwarf cichlids.
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