Redfish Courtbouillon (cou-be-yon)

One-third cup vegetable oil One-half cup all-purpose flour 1 onion, chopped 4 green onions, chopped One-half red bell pepper, chopped 2 garlic cloves, chopped 1 rib celery with leaves, chopped 4 fresh tomatoes, or 1 large can whole peeled tomatoes, chopped (I use Progresso tomatoes) 1 cup red wine 6 sprigs fresh parsley, chopped 3 bay leaves 1 large sprig of thyme or one-half teaspoon dried thyme 6 whole allspice 2 teaspoons salt One-half teaspoon freshly ground black pepper One-eighth teaspoon cayenne pepper Juice of a lemon 2 to 3 cups water 1 medium-size redfish, cut into 2-inch pieces 1 lemon, sliced