Signature Dish is back with a new episode exploring delectable meals from under the sea. Seth heads into Washington, D.C. to sample FishScale‘s True Blue Maryland Crab Burger; to Peruvian restaurant Pio Pio in Great Falls, VA, for a ceviche called Mahi Mahi Avocado; and to Penn Quarter, D.C.’s Rasika, to try the famous Indian restaurant’s Black Cod.