In Queensland the construction of a number ofweirs and tidal barrages has created barriers to the passage of fish. Fish ladders have been incorporated in a number of structures with varying degrees of success. Conventional fish ladders are clearly constrained in the height they can achieve, both from the point of view of cost, and from the stamina of the fish. The Queensland Water Resources Commission has therefore engaged the Zoology Dept of the Univ of Queensland to investigate the suitability of Denil fish ladders. The purpose of this paper is to provide a very brief commentary on some experience with conventional fish ladders and to outline the progress on the Denil research.