Cynopoecilus Killifish

Cynopoecilus melanotaenia is a small annual killifish from the coastal lowlands of southern Brazil and Uruguay, inhabiting temporary pools and flooded grassland habitats that dry seasonally. Males display an intricate pattern of dark banding on a beige-brown body with vivid orange colouration on the dorsal, caudal, and anal fins — a subtle but striking combination. Females are drab but necessary for breeding.

This species is one of the few members of the small genus Cynopoecilus, which is closely related to the better-known Austrolebias and Simpsonichthys. Care follows annual killifish protocol: a dedicated 30 L species tank with peat substrate, soft slightly acidic water, and daily live foods. Eggs require a dry diapause of 8–10 weeks before re-wetting. Fry are small and require micro-foods initially.

C. melanotaenia is a genuine rarity in the hobby, maintained almost exclusively through specialist South American annual killifish hobbyist networks. Its compact size, attractive male colouration, and fascinating annual life history make it a prized species for killifish completists.

Water: 18–24 °C, pH 5.5–7.0, soft water (GH 1–6) essential. Tank: 30 L species tank with peat substrate; no filtration or gentle sponge filter only. Feeding: Live micro worms, Artemia nauplii, and Daphnia; feed small amounts daily. Breeding: Harvest peat every 3–4 weeks; store eggs dry for 8–10 weeks before re-wetting. Compatibility: Species tank only; too small and specialised for community setups.