The Lake Eacham rainbowfish (Melanotaenia eachamensis) is a species of rainbowfish in the subfamily Melanotaeniidae.

It was once believed to be endemic to Yidyam (Lake Eacham), Queensland, Australia but has since been proven to have a wider range.

The species was initially thought to be extinct due to predation by native fishes—including the Barred Grunter (Amniataba percoides) and Mouth Almighty (Glossamia aprion)—illegally translocated to Lake Eacham in the 1980s.

[2] The species was rediscovered in private aquarists collections and has also been found to have a wider distribution in the Barron and Johnstone River systems.

This species inhabits small creeks and crater lakes, congregating along the shallow margins among aquatic vegetation, fallen logs, or branches.