The national survey "Atlas of Danish Fishes" began in 2006. The project is carried out as collaboration between the Natural History Museum of Denmark (University of Copenhagen) and DTU Aqua (National Institute of Aquatic Resources, Technical University of Denmark (DTU)). In the years 2006-2009, the survey focused on gathering information on freshwater fishes. As a result of the first phase of the project, a comprehensive book (in Danish) was published in 2012: Atlas of Danish freshwater fishes, ISBN-13: 9788787519748. Since 2009, mapping of saltwater fishes has first priority. Data is still collected on fish species occurrences in all Danish waters - both fresh and salt water. The Aage V. Jensen Foundations fund the project. This dataset presents general occurrences of species of Danish fresh water fish, recorded in a given UTM quadrant, in a given year. UTM quadrants have been converted to a decimal degree latitude-longitude center-point with a coordinate uncertainty of 5km.