Wash the fish pieces and pat them dry using a kitchen towel. Rub some salt and turmeric powder on them and set aside
Using half a cup of water make a smooth, fine paste with the coriander seeds, cumin seeds, peppercorns, grated coconut, fenugreek seeds, garlic cloves, diced onions, turmeric powder and the dried red chillies
Heat a wok with the coconut oil and add the mustard seeds
When they splutter, add the sliced onions. Fry them until soft and translucent
Add the curry leaves, the prepared spice paste and mix well over medium heat. Fry until oil separates the pan and the paste dries out
Add the coconut milk and cook for 3-4 minutes
Now add the tamarind pulp, salt, green chillies and a cup of water and let simmer for another 5 minutes
Once the curry starts bubbling, add the fish pieces
Let the fish cook in the curry. This should take around 7-8 minutes
Remove from heat and serve hot with steamed rice and some papad on the side!