Marinate the fish in the above-mentioned (for frying) ingredients and keep aside for 10 minutes.
Heat oil in a pan and fry the marinated fish, keep aside.
Grind the masala (garlic, cumin seed & pepper powder) in a grinder to make the paste.
Heat oil in a pot, add the above-mentioned paste, onion, ginger, green chilly & curry leaves. Saute till it turns light brown.
Add turmeric, coriander powder and saute till raw smell goes off. Next, add coconut milk & mix well.
After it starts to boil, add fried fish and tomatoes.
Once it starts to boil well, add a spoon of oil used for frying the fish.
Next, add some vinegar to taste.