Forktail Blue-Eye Breeding Guide

How to breed the forktail blue-eye (Pseudomugil furcatus): sexing, conditioning, mop or moss spawning, the 21-day incubation and raising the fry.

Overview

Pseudomugil furcatus is a small egg-scattering rainbowfish from rainforest streams of south-eastern Papua New Guinea. It spawns continuously rather than in single large batches, depositing a few eggs daily over a period of several days, which makes it a rewarding subject for the patient breeder.

Sexing

Males display more vibrant colour and patterning than females, and their unpaired fins become noticeably extended as they mature. Females are plainer with shorter fins.

Conditioning

Spawning is more likely at temperatures towards the upper end of the species' range. Conditioning adults on small live and frozen foods raises the rate of egg deposition during warm periods.

Breeding Setup

Two approaches work. The first isolates a small group of six to eight individuals, or a single male with two or three females, in a container fitted with an air-powered sponge filter and a spawning medium of nylon mops or aquatic moss. The second keeps adults in a larger planted aquarium where fry can survive among the vegetation; mosses of the genus Taxiphylum attached to decor high in the water column reportedly give the best results.

Spawning Behavior & Trigger

This is an egg-scatterer with no parental care. Males mate with multiple females through the daylight hours during warm periods, and females attach a few eggs daily to aquatic vegetation or other substrate over several consecutive days.

Egg & Fry Care

Incubation lasts around 21 days depending on temperature. The fry can accept Artemia nauplii, microworm and similarly sized foods immediately on hatching, and should be fed at least twice daily. Regular small water changes are essential, as aged water can cause high fry mortality.

Common Challenges

The continuous, low-volume spawning means eggs and fry of different ages share the tank, so colony rearing among dense moss is often easier than collecting eggs. Stable warm water and clean conditions are the main keys to fry survival.