ITOFF collates data on the life-history traits of invasive freshwater fish and those species they impact. Our aim is to facilitate the comparative study of invasive freshwater fish on a broad scale to improve the global management of invasive species. The current version of ITOFF contains data on 303 species, representative of the most prevalent invasive freshwater fish, those species they critically endanger, and species known to be impacted by invasive species but not facing any elevated risk of extinction.