River Blackfish were known from nearby Muckleford Creek in the 1940s and are presumed to have been in Campbells Creek. They are almost certainly extinct here now. Goldrush era siltation and pollution of the stream would have temporarily wiped them out, but their long term local extinction is most likely due to competition and predation from introduced fish, especially trout and redfin.
Read more about and see more of this fish at the Fishes of Australia web site.
Read more about this fish at the Wikipedia web site.