Ruby Red Pencilfish Breeding Guide

Nannostomus rubrocaudatus has been bred in aquaria, albeit rarely. Use densely planted containers with fine mops; first fry appear a day or two after spawning.

Overview

Nannostomus rubrocaudatus is a slender Peruvian pencilfish collected from Saramirisa on the banks of the Maranon (upper Amazon) between the Morona and Santiago rivers in western Peru. Seriously Fish records a size of 25-30 mm SL. Though gregarious, it is a shoaling rather than schooling species, with territorial rival males sparring regularly.

Sexing

Adult males are noticeably less stocky and far more colourful than females, and possess a modified anal fin with the third to sixth rays thickened (Seriously Fish).

Conditioning

As a micropredator it should receive daily meals of small live and frozen fare such as Artemia nauplii, Moina and grindal worm, plus appropriately sized dried foods. Soft, acidic water suits it: Seriously Fish gives 24-28 C, pH 4.0-7.0 and hardness 18-90 ppm. A base footprint of at least 90 x 30 cm is recommended for the group.

Breeding Setup

Seriously Fish notes that successful breeding uses densely planted containers with fine-wool mops or plants, providing spawning sites and protecting the scattered eggs, which receive no parental care.

Egg & Fry Care

Reproduction has been achieved in aquaria, albeit rarely. The adults can be removed after 2-3 days and the first fry should be visible a day or two later (Seriously Fish). The smallest live and prepared foods are required for the first-feeding fry.