Patrizi's Killifish (Nothobranchius patrizii) Breeding Guide

Breeding the East African annual killifish Nothobranchius patrizii: peat spawning, dry diapause incubation, and rewetting to hatch a notoriously delicate species.

Overview

Nothobranchius patrizii is a small annual killifish of East Africa, recorded by FishBase from Kenya and Somalia and reported from the Wabi Shebele basin in Ethiopia. It reaches about 5 cm and lives in temporary pools, swamps and ditches of the coastal plains at 23-30 °C. FishBase notes it is very difficult to maintain in the aquarium.

Sexing

Males display a powder-blue body with red speckling and a lemon-yellow tail, 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. Steady, high-quality feeding is especially important given its delicate reputation.

Breeding Setup

Provide a small species tank with a container of soft peat for spawning. As a bottom spawner it buries its eggs in the substrate, so a layer of fine peat or coir is provided for the fish to dive into. Soft water and subdued light help the pair settle.

Spawning Behavior & Trigger

The fish spawn by diving into the peat and depositing eggs within the medium. The egg-bearing peat is collected and gently squeezed to a damp consistency before being sealed for incubation, mirroring the drying of its natural pools.

Egg Diapause & Hatching

Following the general Nothobranchius pattern, the damp peat is stored at room temperature while the embryos develop and may pause in diapause. After the storage period the peat is flooded with soft, cool water, and the embryos hatch on detecting submersion. Because the species is hard to maintain, careful control of incubation moisture and temperature is essential.

Common Challenges

Its reputation for being difficult in captivity extends to breeding: small errors in storage moisture or wetting timing readily cause failed hatches or weak fry. Patience and a second drying-and-wetting cycle for unhatched eggs improve overall yields.