Preheat the oven to 180C fan-forced (200C conventional). Place the prawns, snapper, salmon and flour in a bowl and gently toss to coat. Add the creme fraiche, corn, leek, chilli and lemon zest and mix to combine.
Season with salt and pepper and divide between 4 x 1 ½ cup capacity ovenproof dishes. Top with stock.
Cut the pastry sheets into circles that are 3cm larger than the ramekins. Brush the ramekin edge with beaten egg to help it stick, press a pastry on top, then brush the top of the pastry with egg. Sprinkle with pepper.
Place on a baking tray and bake for 30 minutes, then serve.
