In a large frying pan over medium heat sauté with olive oil the sweet potatoes and the chopped onion for 5 minutes.
Add the bell peppers, red and yellow, chicken stock and the zucchini. Cook for 5 minutes. Season with salt and pepper. If a bit dry add more chicken stock. At the least minute add 2 tablespoons of butter to blend.
Mix panko and the semolina in a plate. Season to taste with salt and pepper. In another plate add some milk. Dip the fillets in the milk and then in the panko-semolina mixture. Press the mixture well on the fish.
In a large skillet, over medium heat, add olive oil and butter. When the butter is melted and starting to foam, add the fillets. Do not crowd the pan. Press on the fish and let it cook 3 to 4 minutes before turning over. The bottom needs to look golden brown. Turn the fish over with a fish spatula, and cook the other side for another 2 minutes.
Place the fillets on a plate and pour desired amount of relish over.