Clean and cut the fish into thin slices. Apply salt generously.
Grind together the coconut, red chillies, corriander, peppercorns and garlic cloves into a fine paste.
In a pot put in the ground paste along with tumeric powder and bring to a boil. Then add the fish and salt to taste. Lower the flame and let cook till the fish is tender. Lastly add the kokum. Serve over hot white rice.
You can add coconut milk and use powder masalas for the rest of the spices.