 Of salt water fish, Alaska pollock is the most common.Popular freshwater fish on the German menu are trout, pike, carp, and European perch also are listed frequently.Seafood traditionally was restricted to the northern coastal areas, except for pickled herring, which was often served in a Fischbrötchen, as "Rollmops" (a pickled herring fillet rolled into a cylindrical shape around a piece of pickled gherkin or onion), or "Brathering" (fried, marinated herring).