Tube-mouth Pencilfish Breeding Guide

Nannostomus unifasciatus is not thought to have been bred in captivity; earlier reports apparently referred to N. eques. It needs soft acidic water.

Overview

Nannostomus unifasciatus is a slender, oblique-swimming pencilfish from the upper Amazon and Orinoco systems and the Essequibo and Demerara rivers in Guyana. Seriously Fish records a size of 35-40 mm SL. It is a top-dwelling micropredator that prefers calm water.

Sexing

Males are more colourful and typically slimmer than females, with an enlarged anal fin (Seriously Fish). Females are rounder-bodied.

Conditioning

As a micropredator it should receive daily meals of small live and frozen fare such as Artemia nauplii, Moina and grindal worm alongside dried foods. Soft, acidic water suits it: Seriously Fish gives 23-28 C, pH 4.0-7.0 and hardness 18-179 ppm. The species is gregarious and best kept in groups of ten or more.

Common Challenges

Because confirmed spawning records do not exist and historical accounts likely referred to N. eques, no species-specific spawning trigger, egg behaviour or fry-rearing data can be cited for N. unifasciatus.