Heat the oil and fry 8 onions till light brown. Add the ground spices along with the tomatoes, cook until a distinct aroma arises and oil rises to the surface.
Add the fish, stir gently so as not to break the pieces. Simmer over low heat until done.
In a separate pan fry one onion till transparent. Add 1 tsp masala that was set aside, and turmeric with some water at the same time to avoid burning the spices.
Add 1-2 chopped tomatoes and fry. Add rice and fry for a further 5 minutes, add coconut milk and enough water to cook the rice.
Serve on a flat dish, alternating layers of rice and fish.