Breeding Pacific Blue-eye (Pseudomugil signifer)

Breeding Pseudomugil signifer: sexing by male finnage, daily adhesive eggs on plants or mops, 10-21 day incubation and fry care.

Overview

Pseudomugil signifer is a small blue-eye from the eastern Australian coastline, ranging from southern New South Wales north to Cape York and occupying slow streams, estuaries, dune lagoons and salt marshes. Seriously Fish gives a maximum standard length of 35-70 mm, with northern populations larger. It is a continuous spawner: females deposit a few eggs daily over several days, attaching them to vegetation or other surfaces by adhesive filaments.

Sexing

Males are more colourful and patterned, and as they mature their unpaired fins become noticeably extended, sometimes with filamentous tips that are often lost in captivity. Fins may take on orange tones in the spawning season, while females stay plainer and lack the ornamentation.

Conditioning

Maturity comes early, with females ready at around six months. Condition the group on small live and frozen foods; in nature the species is a visual forager taking small insects, flying insects and tiny crustaceans, so varied small foods suit it well.

Breeding Setup

• Provide fine-leaved plants or spawning mops, where Pacific blue-eyes spawn in moss or at the base of plants.
• Spawning peaks in late morning to early afternoon at water temperatures of 24-28 degrees C.
• The species is euryhaline and tolerates a wide salinity range.

Spawning Behavior & Trigger

A single male may mate with several females during one day. Females deposit a few adhesive eggs daily over a period of several days, the eggs hanging from plants or mop by fine filaments rather than being released in one batch.

Egg & Fry Care

The incubation period is 10-21 days depending on temperature. The fry are comparatively easy to start and can accept Artemia nauplii, microworm and similarly sized foods immediately, fed in small amounts at least twice daily.

Common Challenges

Females naturally survive about one reproductive season and become less productive after 12-18 months even in well-kept aquaria, so breeding is best timed to younger, vigorous fish. Collecting eggs daily from the mop and hatching them separately improves yields. Wikipedia notes that the species is euryhaline and adjusts to changing salinity by altering its swim-bladder volume over several hours, so any salinity changes during breeding should be made gradually to avoid stressing the broodstock.