Eastern Splendid Rainbowfish Breeding Guide

How to breed Melanotaenia splendida splendida, an eastern Australian rainbowfish; a pairing plant-spawner laying adhesive eggs on vegetation that hatch in about a week.

Overview

Melanotaenia splendida splendida is the eastern subspecies of the splendid rainbowfish, occurring in eastern Queensland rivers from the Torres Strait Islands and Cape York Peninsula south to the Dawson River according to Wikipedia. The species reaches up to about 20 cm standard length per FishBase, though most aquarium fish are smaller. It is a pairing plant-spawner.

Sexing

Males of the species are the larger, more colourful sex with deeper bodies, while females are plainer. A male can be set up with one or more females for spawning.

Conditioning

The species is omnivorous, feeding on filamentous algae, aquatic and terrestrial insects, small crustaceans and other invertebrates according to Wikipedia. FishBase records reproductive maturity at roughly 3-4 cm. A varied diet conditions the adults for breeding.

Breeding Setup

FishBase lists 20-30 C, pH 6.0-8.0 and hardness 10-30 dH for the species. Spawning is carried out over fine-leaved plants, spawning mops or Melaleuca-type roots, which provide attachment for the adhesive eggs. Breeding takes place year round.

Spawning Behavior & Trigger

According to Wikipedia the male and female form pairs in which the female releases eggs and the male fertilises them; 60-70 golden, round eggs are laid at each spawning and attach to submerged vegetation by an adhesive filament. FishBase cites a total fecundity of around 370 eggs released over a series of spawnings.

Egg & Fry Care

Wikipedia reports the larvae hatch after around a week, are about 4 mm long with a reduced yolk sac and fully formed mouth and pectoral fins, and start to feed after 24 hours. The egg-laden plants or mops can be moved to a separate rearing container, and the small fry require very fine first foods such as infusoria before Artemia nauplii.

Common Challenges

As with other rainbowfish, the main difficulty is the tiny size of newly hatched fry, which need very small first foods. Removing egg-bearing mops protects the scattered eggs from predation.