Golden Pencilfish Breeding Guide

Breeding the golden pencilfish (Nannostomus beckfordi): sexing by colour and anal fin, an egg-scattering free spawner, spawning over fine plants or mesh, and rearing tiny fry.

Overview

The golden, or Beckford's, pencilfish, Nannostomus beckfordi, is an egg-scattering free spawner that shows no parental care. In well-planted, established aquariums fry may appear without intervention, but a controlled setup gives far better yields.

Sexing

Adult males are more intensely coloured, especially when in spawning condition, while females are noticeably rounder-bodied. The male's anal fin has a curved posterior edge that is straight in the female, providing a reliable structural sexing cue.

Conditioning

Condition the adults well on daily small live and frozen foods such as Artemia nauplii, Moina and grindal worm. A single well-conditioned pair, or a group of one to two males with several females, can then be introduced to the spawning setup.

Breeding Setup

Use a smaller, dimly lit tank filled with mature water. Because the species readily eats its own eggs, the base can be covered with a mesh that lets eggs fall through but keeps the adults away, or with plastic 'grass' matting or glass marbles. Fine-leaved plants such as Taxiphyllum or spawning mops also work well, and an air-powered sponge filter or air stone provides gentle oxygenation. Slightly acidic to neutral water at the upper end of the normal range, around 21-27 degrees C, suits spawning.

Spawning Behavior & Trigger

The pair scatter eggs freely over the spawning medium, with the eggs dropping through the mesh or settling among the fine plants out of reach of the adults. Spawning typically occurs over the first day or two after introduction.

Egg & Fry Care

Remove the adults after two to three days to protect the eggs. The first fry should be visible around three days later. Start the fry on Paramecium or a proprietary dry food of 5-50 micron grade, progressing to Artemia nauplii and microworm once they are large enough to take them.

Common Challenges

Egg predation by the parents is the chief risk, so a mesh or marble base and prompt removal of the adults are important. The very small first foods must be available in adequate density, since the fry are tiny at hatching and depend on micro-organisms before they can accept brine shrimp nauplii.