The Australian Museum recently received from Flight Lieutenant Stuart Campbell, R.A.F., of Port Moresby, Papua, a fine series of freshwater fishes collected by him from the upper Fly River, Papua, about thirty miles above d'Albertis Junction. When identifying this collection from such a little known region; I examined a few other species from remote parts of New Guinea, and now put these on record in view of the interest which is nowadays being taken in the fauna of that country. The freshwater fishes of the Fly River are allied to those of other rivers along the southern coastline of New Guinea and also to the fluviatile species of the Aru Islands, Port Essington, and the Northern Territory generally, and the rivers of the Gulf of Carpentaria. The northern New Guinea freshwater fauna is quite distinct from the southern. In this paper, fishes from both areas are discussed, also an interesting eel from the interior.