A fish that lives in the ocean but swims upriver to breed in freshwater, like an eel.
From Greek 'kata' (down) + 'dromos' (running), referring to fish that migrate downriver to the sea and back—literally 'running downward'.
Eels are the ultimate catadrome travelers—they're born in the Sargasso Sea, swim thousands of miles to freshwater rivers in Europe and America, spend years growing, then return to the sea to spawn!
Complete word intelligence in one call. Free tier — 50 lookups/day.