If small, the fish may be served whole; otherwise cut into steaks, filets or other such portion-size pieces. A whole fish may be molded with or without its skin but usually with its head. Clean and wash fish and sprinkle inside and out with lemon juice. Let stand 20 minutes, then pat dry. Poach fish in fish or vegetable stock to cover, flavoring stock with vinegar. When fish is done, remove carefully from stock, drain and lay in large shallow but rimmed dish, such as pie pan, or individual dishes. Let cool thoroughly. When gelatin has softened, add it to the 2 cups hot stock in which fish was poached. Stir until gelatin is completely dissolved. Cool until slightly thickened but not set. Pour over cool fish to cover. Chill until completely set, 1 to 2 hours Fish In Aspic