Since the development of the enature®  fish pass  in 2009 (Austria patent No. 507195, pending patent application EU A 1305/2008, u.Z. 30971) more than 30 fish passes are built in Austria, Germany, Italy and Switzerland and another 20 fish passes are under construction. The actual finished fish passes cover the fish regions from large epipotamal rivers to small epirhithral rivers and from less than 2 m to up to 20 m of drop height. Function analyses are available for all fish regions. The functioning for up- and downstream migration was verified with trap analyses and/or video monitoring. Monitoring results of the fish passes functionality at up to date erected enature^® fish passes resulted in a score between 1.0 and 1.5 (fully functional). A free passage for all fish species present in epirhithral to epipotamal fish regions is established for upstream migration and for most of them also for migrating downstream the fish pass. The fish pass design as well as the monitoring results will be presented in detail.