Dry roast all the ingredients given under "to roast and grind" until the coconuts turn reddish-brown.
cool and grind it to a fine paste and keep it aside until use.
Soak tamarind in warm water and keep it aside.
Heat coconut oil in a mud pot and crackle mustard seeds.
Fry chopped garlic, chopped ginger, green chillies, small onions, and curry leaves until onions turn brown.
Further, add chopped tomatoes and fry till mushy.
Add prepared masala, water, salt, tamarind water.
mix well. close and cook for 10 minutes.
Open and reduce the flame to low. add the fish pieces, mix gently.
close and cook for 5 minutes.
open, mix once, put off the flame and close again. rest for a few hours before serving.