MijnVISmaat - Exotic fish occurrences in Belgium is an occurrence dataset published by the Royal Dutch Angling Federation and the Flemish Research Institute of Nature and Forest (INBO). It contains alien freshwater fish occurrences recorded through MijnVISmaat, a mobile application used by anglers for catch registration. This app was developed and managed by the Royal Dutch Angling Association (Sportvisserij Nederland: https://www.sportvisserijnederland.nl/). With this app anglers register their catches with a smartphone to create their personal logbook of catches with location, species, length, weight, bait, depth and photos. The app also provides a social platform to share catches and information with fellow anglers. The dataset is part of an effort to mobilize alien species data for Belgium. Here it is published as a standardized Darwin Core Archive and includes for each record an occurrenceID, date, location, sampling protocol, the number of recorded individuals, status (present/absent) and scientific ...