Spotted Blue-Eye Breeding Guide

How to breed the spotted blue-eye (Pseudomugil gertrudae): sexing, mop or moss spawning, the ~10-day incubation, and the tiny first foods the fry need.

Overview

Pseudomugil gertrudae is a tiny egg-scattering rainbowfish that spawns continuously when conditions suit. Females deposit eggs daily over several days, attaching them to vegetation by adhesive filaments, so a single conditioned group produces a steady trickle of eggs.

Sexing

Males are more highly patterned and colourful than females, and their unpaired fins become noticeably extended as they mature. Females are plainer and shorter-finned.

Conditioning

Spawning peaks in late morning to early afternoon when water temperature is between 24 and 28 degrees Celsius. Conditioning adults well and holding the tank in this warm band promotes daily spawning activity.

Breeding Setup

Either isolate a single male with two or three females in a small container fitted with an air-powered sponge filter and a spawning medium of nylon mops or aquatic moss, or run a larger planted colony where fry can survive among the plants. Fine-leaved moss such as a Taxiphylum species both collects eggs and shelters fry raised alongside the adults.

Spawning Behavior & Trigger

Spawning occurs during daylight hours with a peak of activity in late morning and early afternoon. A single male may mate with multiple females in one day, and each female deposits a few eggs daily over a span of several days.

Egg & Fry Care

Incubation lasts around 10 days depending on temperature. The fry are very small at first and need microscopic food such as Paramecium for up to five days before they can take Artemia nauplii, microworm and similarly sized foods.

Common Challenges

The fry's tiny gape is the main hurdle: without infusoria-type first foods, early losses are heavy. A mature, moss-rich tank that grows live microfauna eases the transition through the first days.