Clean and salt the fish, then place in a hollow baking dish. Melt the butter in a saucepan, add the cut-up vegetables, water, salt, pepper and bay leaves. Cook on a medium heat until the vegetables are cooked.

Pour the contents of the saucepan over the fish. Sprinkle with chopped parsley and decorate each fish with a lemon slice. Bake for 40 minutes in a medium oven.