Wash and clean the kudampuli. Soak Kudampuli in a cup of water and set aside. Lightly crush the chopped small onions in a mortar and pestle.
Heat oil in a pan and add mustard seeds. When they splutter add fenugreek seeds, curry leaves and fry it for 30 seconds.
Add small onions,sliced ginger and garlic and saute for 3-4 minutes. Add Kashmiri chili powder, Coriander powder and turmeric powder and fry it for 2 minutes.
Add the soaked kudampuli along with water, and 1 more cup of water to the pan and combine well. Add salt to taste.
Stir in the fish pieces, combine well and cook it covered for 10-15 minutes. Uncover it,add a few more curry leaves, sprinkle a tspn of oil and simmer uncovered for another 3-4 minutes.