Melanotaenia eachamensis

This small rainbowfish is a slender-bodied freshwater fish, typically silvery with faint iridescent stripes along its flanks, and males often display more pronounced coloration and finnage during breeding periods. Like other rainbowfishes, it likely feeds on small invertebrates, algae, and organic detritus, contributing to nutrient cycling and serving as prey for larger aquatic predators within its ecosystem. It forms schools in open water, a behaviour thought to reduce predation risk while foraging.

Melanotaenia eachamensis is endemic to a very restricted area of northeastern Queensland, Australia, historically associated with crater lakes and adjoining wetland systems in the Atherton Tablelands region. It depends on clear, still or slow-moving freshwater habitats, including lakes and inland wetlands, for feeding and reproduction.

The species faces multiple compounding pressures. Genetic introgression from introduced and translocated rainbowfish populations has diluted or replaced original genetic lineages, a particularly severe threat given the species' narrow range. Agricultural runoff, effluent from farming operations, and expansion of crop cultivation have degraded water quality in its limited habitat.

Livestock grazing and logging in surrounding catchments have contributed to habitat disturbance, erosion, and sedimentation. Invasive fish species further threaten native populations through competition and predation.

Conservation attention has focused on identifying and protecting genetically pure populations, along with habitat management within its restricted range in Queensland. Monitoring of water quality and population genetics informs ongoing management decisions, and restrictions on the introduction of non-native fish species have been considered in affected waterways.

Given its extremely limited distribution, ongoing genetic contamination, and continuing habitat degradation, the species remains classified as Endangered with a decreasing population trend. Without sustained management of both genetic integrity and habitat quality, its long-term persistence remains uncertain.