The Fly River is a known hotspot in New Guinea for freshwater fishes, supporting more than 140 species including numerous endemics. Every five years the Ok Tedi Mining Limited Environment Department conducts a fish diversity survey of the Fly River system as part of their environmental monitoring. The survey aims to confirm all known species still occur in the river system, and check the health of refuge areas, being subcatchments where fish species can avoid any effects from the mine and recolonise the system after mine life. The 2024/25 round of sampling included a four week cruise of the Fly River, from the mid-estuary and upstream to above the river port of Kiunga. A highlight of the trip was the rediscovery of Paska’s Blue-eye (Pseudomugil paskai), a species not seen in 40 years, since its first discovery in the early 1980s! The record is from a new area, away from settlements and ‘disturbance’, with healthy breeding populations. Maintaining the quality of this refuge habitat is critical for continued conservation of this and other species, known from nowhere else in the world.