rhamphotheca:  MIGRATORY FISHES Diadromous fish:  Truly migratory fishes which migrate between the sea and fresh water. Anadromous: Diadromous fishes which spend most of their lives in the sea and migrate to fresh water to breed.  (ex: Salmon) Catadromous: Diadromous fishes which spend most of their lives in fresh water and migrate to the sea to breed.  (ex: American Eel) Potamodromous: Truly migratory fishes whose migrations occur wholly within freshwater.  (ex: some populations of Alewife, Brown Trout, and species of Amazonian catfish) Oceanodromous:  Truly migratory fishes which live and migrate completely in the sea.  (ex: Tuna) (via: Wikipedia) (photos: T - spawning Sockeye Salmon by TheInterior; B - American Eel by Claude Nozeres, World Register of Marine Species; Alewife via The Nature Conservancy)
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