Fin's Fish Guide
Oneline pencilfish
The Oneline pencilfish (Nannostomus unifasciatus) is a freshwater fish of the family Lebiasinidae that grows up to 4 cm.
Description
The oneline pencilfish is a small, elongate characin from northern South America, in the Amazon, Orinoco and Guianas basins. The species grows to about 6 cm and has a pencil-shaped, slender body with a continuous dark longitudinal stripe from snout to tail and a red-and-black mark in the lower tail lobe. Characteristically it often swims obliquely with the head up. It lives in calm, plant-rich blackwater streams and eats small zooplankton and insect larvae at the surface. It is a popular aquarium fish and is assessed as Least Concern (LC) by the IUCN.
Frequently asked questions
How do you recognise the Oneline pencilfish?
The Oneline pencilfish has an elongate, eel-like body, is mainly silver-grey and shows a horizontal stripes pattern. Pencil-shaped body; often swims at an upward angle; continuous lateral stripe
Where does the Oneline pencilfish live?
The Oneline pencilfish lives in fresh water and is mostly found around mixed bottom. Northern South America
How big does the Oneline pencilfish get?
The Oneline pencilfish grows to a maximum of about 4 cm.
Is the Oneline pencilfish dangerous to humans?
No, the Oneline pencilfish is harmless to humans. This species is harmless to humans. No specific first aid is needed. Still handle the fish with care: mind the fin rays and the sharp edges of the gill cover, and rinse any scratch with clean water and cover it. For a dirty or deep wound check tetanus status.
Is the Oneline pencilfish edible?
The Oneline pencilfish is not usually eaten.
More photos
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All data
Identification
Appearance
Habitat & distribution
Behaviour & biology
For anglers
Safety
Status & sources
Same genus Nannostomus
More from the family Lebiasinidae
Want the complete picture on the Oneline pencilfish?
Point your camera at the fish and Fin names the species in seconds. Free, and the Oneline pencilfish is one of 12,519 species in the app.