Simple, make a layer of spinach, add a layer of creamy pesto sauce, then the lasagna, then spinach, poached cod, shrimp, sauce, lasagna, spinach, cod, shrimp, sauce, lasagna, sauce, cheese.

No reason a lasagna has to be tomato sauce I also have a great recipe for vegetarian lasagna with a spicy tomato/mushroom layer and a cream/cheese/mustard/broccoli layer.