Rinse fish thoroughly in cold water. Place on rack in a fish poacher or tie fish in cheesecloth, and place in a large shallow roasting pan. Add water and 3 cups wine. Place poacher over 2 surface units; cover with lid. Cook over medium heat 20 minutes or until water starts to "quiver." (Do not boil.) Reduce heat to low; cover and cook 40 minutes. (Do not let water boil.)
Transfer fish to a large platter; remove cheesecloth, if used. Cool; refrigerate until chilled.
Soften gelatin in remaining wine in a small saucepan. Stir in food coloring. Cook mixture over low heat, stirring constantly, until gelatin dissolves. Remove from heat.
Place strips of waxed paper under outside edges of fish. Place radish in eye cavity. Using a soft-bristled paint or pastry brush, paint liquid gelatin mixture over surface of fish; repeat procedure until all gelatin mixture is used. Carefully remove waxed paper. Chill thoroughly.
Garnish platter with endive, watercress, cherry tomatoes, zucchini strips, cucumber slices, and broccoli flowerettes. Before serving, peel off aspic and skin, leaving white fish exposed to serve. Serve cold with Caviar Dip.