Breeding Lake Eacham Rainbowfish (Melanotaenia eachamensis)

Breeding Melanotaenia eachamensis: a conservation-bred species, sexing by male fins, java moss or mop spawning, fry care and its endangered status.

Overview

Melanotaenia eachamensis was once believed to be endemic to Lake Eacham in Queensland, Australia, but has since been shown to have a wider range in the Barron and Johnstone River systems. It was initially thought extinct after Barred Grunter and Mouth Almighty were illegally introduced to the lake in the 1980s, then rediscovered in private aquarists' collections. It is listed as Endangered on the IUCN Red List, so captive breeding has real conservation value. FishBase gives a maximum length of about 6.5 cm.

Sexing

Breeding males show bronze to orange tones with almost-black margins on the dorsal and anal fins, and their fins are longer, more pointed and more brightly coloured than those of females. Females stay plainer with shorter, rounder fins.

Conditioning

As an omnivorous rainbowfish it takes varied dried, frozen and live foods. Conditioning the group on rich foods brings females into spawning condition and intensifies male display.

Breeding Setup

• The species spawns among bushy plants in the wild, so provide java moss and spawning mops in the aquarium.
• Keep either a single pair or a group of 2-3 females per male.
• FishBase lists a pH of 7.0-7.4 and a temperature of 23-27 degrees C.

Spawning Behavior & Trigger

Conditioned fish scatter adhesive eggs into the moss or mop over a series of days, the eggs attaching to the medium by fine threads in the manner typical of the genus.

Egg & Fry Care

The spawning medium can be moved to a separate tank to protect eggs and fry. As with related rainbowfish the small fry start on infusoria-type foods before taking free-swimming foods such as brine shrimp nauplii.

Common Challenges

Maintaining distinct, well-documented bloodlines matters for an Endangered species; mixing with other rainbowfish should be avoided. The history of this fish, once thought extinct in Lake Eacham after illegally introduced predators and later rediscovered in private aquarists' collections, shows how directly responsible captive breeding can support a species' survival. Clean water within the FishBase ranges and small first foods underpin fry survival.