Mix the fish with ginger garlic paste, turmeric powder, red chili powder, salt and yogurt. Marinate this for half an hour in the fridge.
Heat oil in a pan and fry the fishes till lightly brown.
Heat the 2 tbsp oil in a pan add the green chili.
Add the onion paste and cook till it has changed the color to golden brown. Be careful as to not burn the onion. Once the paste changes it's color, it will quickly start burning.
Next throw in the ginger garlic paste and cook till the raw smell from the ginger garlic paste has vanished.
Next add in the tomato puree, red chili powder, coriander powder, garam masala powder and cook on low heat. Cook till oil starts leaving the sides of the pan.
Finally add in the fried fish pieces and mix till all the masala is coated to the fish. Be extra careful while mixing as the fish will break very easily if handled roughly. Be extra gentle.
Finally add coconut milk and adjust the consistency of the masala. Do not add any water if you want a thick version. Just cook till the coconut milk has been absorbed into the fish. Add little water and cook till it comes to a boil and remove from heat.
Lastly, add the coriander leaves to garnish the fish masala recipe.