Wash the fish pieces and pat them dry. Then sprinkle little salt and keep aside.
Heat 2 - 3 tbsp of oil in a frying pan. Splutter a handful of curry leaves, add one cup of onion, grated coconut and the star anise and keep stirring till the onion is translucent. Keep a watch on the heat or else the coconut will burn.
Once the raw smell has gone, turn off the heat. Let it cool down a bit and then tip it in a blender and make a paste. The oil helps in grinding. However, if you feel, sprinkle some water in making the paste. This is your wet paste now.
Take the pan again and add the rest of the oil. Once the oil is hot, add the rest of the chopped onions and fry them. Once the onions are translucent, add the wet paste and the chopped tomatoes and continue stirring.
This will probably take about 10 minutes approximately for the onions and tomatoes to cook. Then add the red chili powder, coriander powder, turmeric powder and salt and fry till the raw smell disappears.
Add the tamarind paste and some water and let it cook for 5 minutes. After which stir in some slit green chilies and dunk the fish pieces.
Finally add the coconut milk, salt and simmer for 5 to 8 minutes or until the fish is cooked.
Garnish with more fresh curry leaves and turn of the heat.
Serve it with some steamed rice.