Soak coccum pieces in ½ cup hot water for 5-10 minutes. Set aside.

Place ground turmeric, ground black pepper, and Kashmiri chilly powder in a small bowl. Add enough water, and mix well to make a smooth paste.

Meanwhile, heat oil in a clay pot (traditional vessel used for cooking fish). Splutter mustard and fenugreek seeds. Add in shallots and fry until golden brown. Then throw in ginger and garlic. Fry for a few seconds.

Now add in the chilly paste and fry, stirring, for a few more minutes. When oil appears on the surface, add in coccum along with the water. Place the fish pieces one by one in the chilly mixture. Add more water just to cover the fish pieces.

Now throw in the curry leaves, and add enough salt. Cover the pot with a lid, and bring it to a boil. Then, lower the flame, and let the curry simmer for 10-15 minutes, or until the fish pieces are well cooked.