Cut fish into small pieces.

Boil kudam puli with 1/2 cup of water in a deep vessel(preferably meen chatti) for 5 mins.

Grind together shredded coconut, chilly powder, turmeric powder, coriander powder, ginger and a small onion, into a smooth paste along with a little water.

Add the above paste along with the fish pieces into the deep vessel.

Add green chillies and curry leaves.

Add salt to it and mix well.

Cover and simmer, until the fish is cooked through and tender.

Heat oil in a small frying pan. Splutter mustard seeds.

Add the chopped small onions and fry, till they turn brown in colour.

Pour this into the cooked fish curry.

:- Serve hot with rice or kappa(tapioca).