From the biological point of view, fishways are structures that enable fish to continuetheir migration past obstructions. In terms of hydraulics, fishways are energy dissipatingstructures. One of the most effective fishways in energy dissipation is a Denil fishway. This paperpresents the most important results of the studies on Denil fishways carried out at the Hydraulicsand Water Resources Engineering Laboratory at the University of Oulu. The studies were focused on Denil fishways with wide relative baffle width (B/b = 2). Dimensionless discharges forDenil fishways with B/b = 2 are higher for the same water depth than for the standard Denilreflecting higher water velocities in the cross section. The dimensionless discharge curves for thestandard Denil and for designs with different baffle angles are quite close to each other. Theexperiments show, however, clear trends in using different baffle angles to the bed.