1. In a mixer blend coconut milk with turmeric powder and red chili powder.
2. Heat a pan and add the blended coconut milk mixture.
3. Add salt and tamarind and boil for about 10 minutes.
4. When the mixture gets a little thicker, add the fish, onion, curry leaves, ginger and tomato.
5. Cook for about 6 or 7 minutes until the fish softens.
6. For seasoning, in a pan heat coconut oil and add the chopped pearl onion.
7. Stir until it turns brown and add some curry leaves if desired.
8. Sprinkle the seasoning over the curry and serve with roti or rice.