Fish in DC?
Like the previous poster said, avoid restaurants on the Maine Avenue waterfront. Kinkeads is always a good choice, as is DC Coast. Both have websites with copies of their menus--www.kinkead.com and www.dccoast.com. You also might want to consider Palena (on Connecticut Avenue, north of the zoo). I ate there just last night and was served a wonderful red mullet as part of a five-course tasting menu. The chef, Frank Ruta, was just named one of the ten best new American chefs by Food and Wine. The meal and the wine pairings were fabulous. Enjoy your stay in DC!