Clean, wash and cut the fish into medium sized pieces. Add a pinch of turmeric while washing the fish.
Marinate the fish with 2 tbsp fish masala powder, 1/2 tsp ginger paste, 1/2 tsp garlic paste and salt. Keep it aside for half an hour.
When the onions turn brown, add the ground masala paste along with 1 cup water and salt.
When the gravy starts boiling, add the fish pieces and kudam puli/gambooge pieces. Add more water if required, so as to cover the fish pieces.
Sprinkle some uluva/fenugreek powder. Cover and cook Nadan Meen Curry on gentle heat for around 15 minutes. If you like the taste of cilantro, garnish with a handful in Nadan Meen Curry.