Kilombero Nothobranchius (Nothobranchius kilomberoensis) Breeding Guide

Breeding the Tanzanian floodplain annual killifish Nothobranchius kilomberoensis: peat spawning, dry diapause, and rewetting to hatch fry.

Overview

Nothobranchius kilomberoensis is an annual killifish endemic to the Kilombero River basin in Tanzania. FishBase records males to about 3.4 cm and females to 4.1 cm standard length, living close to the substrate of ephemeral pools that usually dry up seasonally, favouring areas with dense grass cover. It is listed as Vulnerable on the IUCN Red List, reflecting its restricted range and dependence on seasonal wetlands.

Sexing

Males carry bright blue scales and a deep red caudal fan, while females are smaller and plain; the female grows slightly larger in body than the male. 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. Consistent feeding keeps females producing eggs daily over the spawning substrate.

Breeding Setup

Provide a small species tank with a container of soft peat for spawning. The fish bury their eggs in the substrate, so a layer of fine peat or coir is offered for them to dive into. Soft water and subdued light keep the group calm.

Spawning Behavior & Trigger

The fish spawn by diving into the peat and depositing eggs in the medium throughout the day. The egg-bearing peat is collected and gently squeezed to a damp consistency before sealing for incubation, recreating the seasonal drying of the floodplain pools.

Egg Diapause & Hatching

Following the standard Nothobranchius method, the damp peat is stored at room temperature while 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. Adjusting storage temperature and moisture controls how long development takes.

Common Challenges

As with other annual killifish, storing the peat too wet or too dry disrupts diapause and lowers hatch rates. Eggs that fail to respond to the first wetting can often be re-dried and wetted again after a further rest.