Breeding Sepik Rainbowfish (Glossolepis multisquamatus)

Breeding Glossolepis multisquamatus, a Sepik floodplain rainbowfish: sexing, soft acidic plant spawning and rearing the fry.

Overview

Glossolepis multisquamatus is a New Guinea rainbowfish from the Sepik region, described by FishBase as the only known floodplain-dwelling rainbowfish, inhabiting swampy lagoons, lakes and small side channels of large rivers. FishBase gives a maximum length of 12.0 cm for males and 10.0 cm for females and classifies it as a plant spawner; unusually for the family it is described as carnivorous, feeding on small invertebrates taken from mid-water or the surface. It is listed as Least Concern.

Sexing

As in the genus, males grow larger and more strongly coloured than females, with deeper bodies, while females stay smaller and plainer. The pale silvery body shows golden mid-line marks and peach tones most strongly in mature males.

Conditioning

FishBase reports a carnivorous diet of small invertebrates, so condition the group well on live and frozen invertebrate foods taken from mid-water or the surface until the females are full of eggs.

Breeding Setup

• As a plant spawner it needs fine-leaved plants such as java moss or nylon spawning mops.
• FishBase gives a soft, acidic profile with pH 6.2-6.8 reflecting its floodplain habitat.
• FishBase lists a temperature range of 26-30 degrees C.

Spawning Behavior & Trigger

FishBase classifies the species as a plant spawner. Like other rainbowfish it deposits adhesive eggs among fine plants or the mop, the eggs attaching by threads and being released over a series of days.

Egg & Fry Care

Move the spawning medium to a separate tank for hatching. As with related rainbowfish the small fry start on infusoria-type foods before taking free-swimming foods such as brine shrimp nauplii.

Common Challenges

Its preference for soft, acidic floodplain water differs from many rainbowfish, so matching the FishBase pH range of 6.2-6.8 supports spawning. As the only known floodplain-dwelling rainbowfish, with a carnivorous habit of taking small invertebrates from mid-water and the surface, it also benefits from rich invertebrate conditioning foods rather than a vegetable-heavy diet. Clean water and small first foods are key to raising the fry.