1 Drain liquid from peas and corn into a medium-size saucepan.
Stir in soup and evapo-rated milk; heat to boiling.
2 Combine peas, corn, tuna, pimientos, and onion in shallow 8-cup baking dish; pour boiling soup mixture over; stir to mix.
3 Bake in hot oven (400°) for 20 to 25 minutes, or until bubbly-hot.
4 While tuna mixture bakes, make and bake pastry topping: Prepare piecrust mix, following label directions.
Place on lightly floured cookie sheet on a damp towel to prevent slipping; roll out to a shape about 1 inch smaller than top of baking dish.
5 Trim edges evenly or, to make a fish design as pictured, cut around a fish shape (cardboard or plate).
Mark "scales" by making shallow curved cuts, holding sharp-point knife on a slant.
6 Bake in hot oven (400°) for 12 to 15 minutes, or until golden-brown.
7 Slide on top of bubbling tuna mixture.
Mark eye with a pea, parsley sprig, or a bit of pimiento.