Hydropus moserianus is a species of agaric fungus in the family Marasmiaceae. Found in the Netherlands, it was described as new to science in 1983 by Dutch mycologist Cornelis Bas. The specific epithet honours Austrian mycologist Meinhard Michael Moser. Fruit bodies of the fungus have reddish-brown to dark greyish-brown caps measuring . The gills are distantly spaced, numbering 12 to 16, and have a decurrent attachment to the stipe. Its spores are amyloid, and measure 8.2–11.1 by 4.2–5.7 μm.
