Repeated mass fish death events in the Menindee weir pool have become serious ecological and cultural issues in western NSW. In February and March 2024, thousands of adult Golden Perch died within the Menindee weir pool over a period of four to six weeks with no clear cause. Unlike previous fish kills, dissolved oxygen was within survivable thresholds and only one species appeared effected. Water quality, cyanobacteria and sediments were analysed and within acceptable ranges with no clear change in antecedent conditions. Golden Perch feeding behaviour differs from other species in the system by preferentially feeding on animals within the benthic zone. Analysis of dead golden perch found very high parasite loads externally and internally with several of these parasites having life stages within crustaceans and benthic worms. It is currently unknown what caused such significant parasite loads within the Menindee weir pool, however we contend previous fish kills, reduction in flow velocities, sulfidic sediments and high nutrient loads potentially all played a role in creating a perfect breeding ground for benthic parasites. Research is continuing however, remediation of riparian zones and increased flow velocities to “more natural” conditions have been found to reduce parasite baring taxa like tubificid worms.