Soak tamarind paste in water to extract liquid.
Heat vegetable oil in a traditional clay pot or pan, sauté curry leaves, sliced onions, ginger paste, and garlic paste until soft.
Add Kashmiri red chili powder, turmeric powder, tamarind extract, salt, and water; bring to a boil.
Gently place fish pieces into the boiling gravy and simmer for 8 minutes.
Stir in coconut milk, heat through gently without boiling, and serve hot with steamed rice.