Pour oil in a wok or chatti(earthern pot) and fry in the following order: first splutter mustard seeds. Then add sliced shallots, garlic, ginger and green chillies. Fry for a few minutes.
Add curry leaves and stir in the mixture of powder ingredients. Fry well till oil separates.
Add water and boil. When the gravy boils, add the fish and kudampuli. Cover the wok till it boils. Lower the flame and allow the fish to cook. When the gravy thickens remove from fire.