The present invention relates to an aeration device (10) for increasing dissolved oxygen in flowing water and supplying the same into a stagnant or flowing water reservoir or water chamber, wherein the device (10) comprises a tubular body (11) having a water inlet (14), a water outlet (16) as well as a subdividing device (40) for separating an incoming water flow into flow lines. Said subdividing device (40) is located at the outlet (16) and comprises a number of wings (30, 30) having an upper surface (31) and a planar bottom surface (32) which is comparatively larger than the upper surface (31) said wings (30, 30) define water passageways (41) narrowing from up to down in direction of water flow through the outlet (16).
