Abstract: A water aerating device is provided and includes a rigid, round, support plate that in an operating position is disposed essentially horizontally. An elastic plate rests on the support plate and is provided with a plurality of fine slits such that by at least one opening of the support plate, air can be introduced between the support plate and the elastic plate for expanding the slits. The elastic plate has an annular rim that rests against an outer surface of the support plate. A fastening ring surrounds the support plate and is axially displaceable relative thereto. A radially inwardly directed projection of the fastening ring acts upon a rim of the elastic plate such that displacement of the fastening ring in a fastening direction results in an increase of the distance of the rim from the upper surface of the support plate.