Heat the pan and add 1/2 tsp cumin seeds, mustard seeds, fenugreek seeds, ginger, garlic, cinnamon stick, curry leaves, fry until the aroma comes out. Grind the fried ingredients with little water into paste.
Heat the pan with oil and add chopped onion, tomato and fry until it gets golden brown. Add cumin powder, chili powder, turmeric powder, coriander powder fry until the aroma comes out and add ground paste.
Let it boil and add salt and cleaned fish head. cook in the medium heat until the fish is cooked well. Add coconut milk and cook for 3 min in the simmer.