Wash and soak dried fish in warm water for 10 mins. Drain and set aside.
Take tamarind in a bowl, add water and soak for 10 mins. Drain and take it in a earthernware pot.
Add in chopped onions and all ingredients except oil and fish.
Bring it to a boil, boil for 5 mins.
Now add in oil and boil for 5 more mins.
Add fish and cook till fish is cooked.
Take it off the heat and let it stand for 1 hour for the flavour to develop.
Serve with rice.