Lake Eacham Rainbowfish
The Lake Eacham Rainbowfish was discovered in Lake Eacham on the Atherton Tableland near Cairns, Queensland. Lake Eacham is an isolated crater lake. The Lake Eacham Rainbowfish disappeared from Lake Eacham in the late 1980's. Genetic analysis of rainbowfish populations in north Queensland has revealed other populations in Lake Euramoo, Dirran Creek, Charappa Creek and other streams on the northern Atherton Tableland (QLD).Features:
Rainbowfishes can be recognised by their thin deep body and bright colours. The Lake Eacham Rainbowfish may be difficult to distinguish from other rainbowfishes in the region. There are minor differences in tooth pattern and body shape between species. Lake Eacham Rainbowfish from Lake Eacham generally have a silvery or bluish body with a dark mid lateral stripe and orange stripes above and below. The fins are clear to yellowish orange. Lake Eacham Rainbowfish from other places vary in body and fin colour, but tend to retain the same pattern. Males tend to be more brightly coloured and have dorsal and anal fins that end in a point. The dorsal and anal fins of females are more rounded. Lake Eachan Rainbowfish grow to about 65 mm.Ecology/Way of Life:
The Lake Eacham Rainbowfish is biologically similar to other rainbowfishes. They inhabit lakes and creeks, usually in shallow, clear water. They are omnivores and eat algae, insects and planktonic crustaceans. They breed throughout the year except for the cooler months. Females scatter a few eggs every few days over aquatic plants. The eggs have sticky tendrils that attach to the plants. The eggs hatch in 7 to 10 days. The fry grow quickly and are mature at about 30 mm.Interaction with Humans/Threats:
The Lake Eacham Rainbowfish were extirpated from Lake Eacham when other native fishes were introduced to the lake. The four species introduced were Barred Grunter (Amniataba percoides), Sevenspot Archerfish (Toxotes chatareus), Mouth Almighty (Glossamia aprion) and Bony Bream (Nematalosa erebi). It is thought that these species competed for food and habitat and ate the eggs, fry and adult rainbowfish. For a few years Lake Eacham Rainbowfish were only thought to exist in captivity. With the discovery of other populations nearby, their conservation status has been down-listed from Extinct in the Wild to Vulnerable. Lake Eacham Rainbowfish are excellent aquarium inhabitants and are readily available.Other Comments:
Melanotaenia eachamensis was named by Allen and Cross in 1982, Melanotaenia meaning black bands and eachamensis from where the species is found, Lake Eacham.Further Reading:
Allen, G. R., Midgley, S. H. & Allen, M. (2002). Field Guide to the Freshwater Fishes of Australia. Western Australian Museum. Perth. 394pp.
Text: Rob Wager & Peter J. Unmack. Distribution map: Peter J. Unmack. Photographer: Neil Armstrong.Sponsorship welcomed:
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