The flowing aerator is composed of stainless steel waterproof motor and high-intensity plastic parts, which have the good corrosion resistance. The shaft-sealing parts of its waterproof motor floats above the water level when it is not active, thus greatly lowering the possibility of the water intake caused by the damaged motor seal so as to achieve long life span. In operating, the stainless steel motor is in the water passageway to produce excellent cooling effect. The water intake pipe can be lengthened expediently if necessary, and also has the aeration effect to deep water. This aerator is lightweight and easy for installation and use, applicable for aeration in ponds for fish, shrimp and other aquatic species; its fountain-shape water flow is also a pretty vision, adding a lively touch to the landscape in the pond, lake or park.