Diadromous fish travel between salt and fresh water. Anadromous fish live in the sea mostly, breed in fresh water; the best-known are salmon, which hatch in small freshwater streams, go down to the sea and live there for several years, then return to the same streams where they were hatched, spawn, and die shortly thereafter. Salmon are capable of going hundreds of kilometers upriver, and humans must install fish ladders in dams to enable the salmon to get past. Catadromous fish live in fresh water, breed in the sea; the most remarkable are freshwater eels of genus Anguilla, whose larvae drift on the open ocean, sometimes for months or years, before travelling thousands of kilometres back to their original streams. Amphidromous fish move between fresh and salt water during some part of life cycle, but not for breeding.