For the ground masala, Heat oil in a small saucepan. Roast the coconut, shallots and fennel till browned. Ensure not to burn.
Allow to cool and then grind into a paste with the water.
Heat oil in a chatti (earthen pot). Add the fenugreek seeds. As it starts smelling fragrant, add in the onion and chillies and saute till wilted.
Add the ginger garlic paste and saute till the raw smell is gone.
Squeeze out the tamarind well and pour the water into the mixture. Add another 1/2 cup of water and squeeze the tamarind again. Pour the water in and discard the tamarind.
Add in the powders and tomato, mix well and allow the mixture to boil. Add salt.
Add the fish and cook till done.
At this stage, add the coconut paste and simmer for five minutes. Add the curry leaves and switch off.
Serve hot with steaming rice and any vegetarian side!