Then add sliced onion and saute till it becomes light brown in colour.
Now add chopped tomato and green chilly. Saute for another 5-6 minutes. Then reduce the flame to low and add all the masala powders: red chilly powder, turmeric powder, coriander powder and garam masala. Saute for a minute to rid off the raw smell.
Squeeze out all the water or oil from the canned tuna. If you are using fresh fish, cook the fish with turmeric powder, salt and water. Cool and shred fish meat finely, remove the bones and keep it aside.
Add cooked shredded tuna or canned tuna along with enough salt to the previously prepared masala mixture and mix well. (Note: Canned tuna is already cooked, so we don't have to cook it before.)
Cook covered in medium-low flame for 5 minutes. Finally add black pepper powder and curry leaves and drizzle little oil, if its sticking to the bottom remove from the fire.