Fry seasoned fish in a pan filled with oil until both sides are cooked. Layer the fish in a deep oven dish and set aside. add sliced onions to the pan and cook until see through but still crunchy. Pour into a deep pot and add water, vinegar, turmeric fish masala, and sugar to taste and bring to the boil. Pour over the fish and allow to stand for aprox 24 hrs. Serve cold with fresh home made bread or hot cross buns