Kafue Killifish (Nothobranchius kafuensis) Breeding Guide

Breeding the Zambian annual killifish Nothobranchius kafuensis: peat spawning, a roughly 5-month dry incubation, and rewetting to hatch fry.

Overview

Nothobranchius kafuensis is an annual killifish from the Kafue River and upper Zambezi River in Zambia. FishBase records it to about 6 cm, benthopelagic and non-migratory, with a preferred temperature of 22-28 °C, and notes it is difficult to maintain in the aquarium. It is listed as Least Concern on the IUCN Red List (2018). Adults perish when their floodplain pools dry, while their eggs persist in the substrate.

Sexing

Males show an electric-blue body with orange-red fin margins, while females are smaller and plain. Keep one male with several females in a quiet species tank.

Conditioning

As a carnivore it should be conditioned on small live and frozen foods such as daphnia, bloodworm and brine shrimp. Strong, regular feeding maintains continuous egg output over the peat.

Breeding Setup

Provide a small species tank with a container of soft peat for spawning. As a bottom spawner the fish bury eggs in the substrate, diving into a layer of fine peat or coir. Soft water and subdued light keep the group settled.

Spawning Behavior & Trigger

The fish spawn by pushing into the peat and depositing eggs within the medium through the day. The egg-bearing peat is collected and gently squeezed to a damp consistency before sealing for the long incubation this species requires.

Egg Diapause & Hatching

FishBase records an incubation of about 5 months for this species, so the damp peat is stored for a correspondingly long dry period while the embryos develop and may rest in diapause. After incubation the peat is flooded with soft, cool water, triggering the embryos to hatch on detecting submersion. The long incubation makes patient, stable storage especially important.

Common Challenges

Given the long incubation and the species' reputation as difficult, storage moisture and temperature must be kept stable for months. Eggs that do not hatch on the first wetting can often be re-dried and wetted again after a further rest period.