The dataset contains the total catch number and total weight of the catch of fish species which has been electrofished in the rivers "Grote Nete" and "Kleine Nete" in Belgium. The scope of the project was to make an inventory of fish species abundance and density in both rivers. The data were used to make a red list of fish species in Flanders. To allow anyone to use this dataset, we have released the data to the public domain under a Creative Commons Zero waiver (http://creativecommons.org/publicdomain/zero/1.0/). We would appreciate however, if you read and follow these norms for data use (http://www.inbo.be/en/norms-for-data-use) and provide a link to the original dataset (https://doi.org/10.15468/zan6uj) whenever possible. If you use these data for a scientific paper, please cite the dataset following the applicable citation norms and/or consider us for co-authorship. We are always interested to know how you have used or visualized the data, or to provide more information, so please contact us via the contact information provided in the metadata, opendata@inbo.be or https://twitter.com/LifeWatchINBO.