Grind the fried netholi coarsely and keep it aside. Coarsely grind grated coconut, small onion (2) and green chilli.
Combine the ground fish and coconut.
Heat oil in a wide pan and crackle the mustard seeds. Add remaining sliced small onion and curry leaves. Cook till the onion becomes golden brown in colour. Add crushed red chilli and fry for a min.
Add coconut-fried fish mixture, salt and mix well. Cook on low flame for 4-6 mins.
Notes
Any leftovers can be stored in the fridge for 3-4 days. You can reheat it by microwaving or dry roasting for 2-3 mins on slow flame.