Cubanichthys cubensis Breeding Guide

Breeding the Cuban killifish Cubanichthys cubensis: a non-seasonal plant-spawner whose females deposit up to ten adhesive eggs daily on plants.

Overview

Cubanichthys cubensis, the Cuban killifish, is endemic to Cuba, mainly the west of the island, where Wikipedia reports it from densely vegetated freshwater (occasionally brackish) with open, sunny areas. FishBase classifies it as a non-seasonal killifish and notes it is easy to maintain; the IUCN lists it as Least Concern (2020).

Sexing

Wikipedia gives males at about 3.6 cm with females slightly smaller, and describes the marbled greenish body with bright fin edges of mature fish; males are the more strongly marked sex.

Conditioning

The species is larvivorous, with mosquito larvae forming a significant part of its diet, so conditioning on small live and frozen invertebrates is effective. FishBase lists a temperature range of 23-28 C and pH of 7.0 and above for the species.

Breeding Setup

A densely planted tank with macrophytes or algae suits this hardy rivulid, which tolerates a wider parameter range than most. Fine-leaved plants or spawning mops provide the egg-laying sites it favours.

Spawning Behaviour & Trigger

Wikipedia states that spawning extends over several days, with females depositing up to ten eggs daily, laid individually on plants. The eggs are relatively large at about 1.4 mm in diameter, transparent and adhesive. This continuous, non-seasonal pattern means no dry phase is required.

Egg & Fry Care

Adhesive eggs can be left on plants in a low-predation tank or collected daily for separate incubation. On hatching, fry take microscopic foods followed by newly hatched brine shrimp.

Common Challenges

The low daily egg count means harvesting eggs steadily over days yields more fry than waiting for a single batch. Otherwise the species is undemanding, and clean, well-planted water with stable parameters supports reliable spawning.