Small portable Denil (0.3m width, 0.3m depth) and Steep Pass (0.3m width, 0.3m depth) were experimentally installed on a divergent weir in a brook of 3m width, and also on a concrete channel connected to the fish pond in Shimane Prefectural Fisheries Experimental Station, in order to check the suitability for ayu fish. Although the direct release into the fishway channel resulted in misery, the release into the downstream showed a reasonable success even in the slope of 30% in both Denil and Steep Pass. In was often observed that ayu passed the bottom layer even in Steep Pass.