ITOFF (Invasive Traits of Freshwater Fish) 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 spatial scale to improve the global management of invasive species. The current version of ITOFF contains data on 1892 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 an elevated risk of extinction.