An arrangement on flowing bodies of water in the area of a transverse structure and/or water structure, in the form of a fish migration bypass (13) for transporting aquatic animals, in particular fish, between tail water (4) and head water (5), provided with a substantially vertical shaft (17). The water level in the shaft 17 is variable between the tail water and the head water level. A basket-like transport container (15), which can be moved in the shaft (17) and which is provided on the shaft for transport of aquatic animals, is equipped with floats (16), which are filled with air so that water rises/falls in the shaft (17) from the tail water (4) to the head water (5) and from the head water (5) to the tail water (4).