Heat 2 tablespoon of coconut oil in a heavy bottom pan.
Add ginger , green chili and finely chopped onion . Fry till raw smell goes off.
Now add in chopped tomatoes , pinch of salt and cook till tomatoes look pulp.
Whilst prepare masala paste by blending coconut , chili powder , coriander powder , tamarind, garlic , peppercorns , methi seeds and ajwain into a fine paste. Add little water while blending to make fine paste.
Add this ground masala into above cooked tomatoes.
Saute and cook masala paste for 5 minutes, till rawness of masala paste goes off.
Add ½ cup of mixer rinsed water and cook masala till specks of oil is seen on top.
Now add 3 cups of water and salt to taste , bring it to boil .
Keep flame on medium heat and now add fish pieces .
Close lid and continue to cook for 10 minutes.
When it comes to boil , open lid and keep curry on simmer.
Meanwhile , heat oil in a Tadka / season pan , add curry leaves and chopped onions fry till onions turns brown.
Pour seasoning / tadka over fish curry and turn off the stove.
Serve Fish curry with plain rice or boiled rice.