Over a length of 500 metres, the fish bypass connects the watercourse of the natural Drava in the area of the St. Martin weir with the 16.9 metre-higher headwater channel of the power plant, and is a technical and ecological masterpiece as the longest technical bypass in Carinthia. It consists of a total of 130 pools and 17 resting and spawning zones. Special slots in the pools keep the movement of the water constant and direct the current in an S-shape. This corresponds to the pressure behaviour of natural waters. The bypass is designed for the species of fish that can be found in this section of the Drava. One of the most important of these is the Danube salmon, which, with a length of up to one metre, is the species that determines the size of the project. Brown trout, common nase and barbel also use the ladder to reach their spawning habitats. The subsoil in the fish ladder is also a valuable habitat for microorganisms such as larvae and fish feeders – which is why experts often speak of a migration corridor.