Catfish vendor in Ilorin, Kwara Extant catfish species live inland or in coastal waters of every continent except Antarctica. Catfish have inhabited all continents at one time or another. They are the only ostariophysans that have entered freshwater habitats in Madagascar , Australia, and New Guinea. As invasive species[ edit ] Walking catfish is an invasive species in Florida. Representatives of the genus Ictalurus have been introduced into European waters in the hope of obtaining a sporting and food resource.