Ingredients:
1) Fish pieces 10
2) Coconut 1 and 1/2 cups
3) Red chillies 6-7
4) Ginger 1″ piece
5) Teppal 5-6
6) Turmeric a pinch
7) Kokum pieces 2-3 or thick tamarind juice 1/2 tea spn
Salt

Procedure
Crush coconut with red chillies, ginger and turmeric to a very smooth paste (grind till the blender/mixer becomes real hot).
Add a tea spoon of water along with teppal in a mortar and slightly crush with pestle (only till a white juice is got. The Teppal should not be ground to paste). Some people discard the teppal at this stage and use only the white juice of it, but I like the teppal also in the curry so that the teppal leaves more aroma in the curry as time passes.
Heat the ground masala with sufficient water to get a gravy. Add teppal, kokum pieces (or tamarind juice), salt and cook till the gravy starts boiling. Now add fish (Do not add fish before this, if you do, the fish becomes paste by the time the gravy is cooked) and cook till the fish turns color to white (fish takes around 5-10mins to cook completely).
Serve hot with rice after atleast 2-3 hours from cooking.