Wash fish pieces 3-4 times. Mix 1 tsp salt to it and marinate till it is used or atleast for 30 minutes.
Wash gambooge and soak it in 1/4 cup of hot water. Keep it aside. Chop ginger, garlic and onions and keep it ready.
Heat clay pot. pour coconut oil, add fenugreek seeds, then chopped ginger and garlic.
Saute till light golden brown. Add sliced shallots and saute till translucent. Add chopped coriander leaves. Fry for another 2 minutes.
Add coconut pieces and grated coconut. And immediately switch off the flame. Mix everything well and let it cool down. Grind it to a fine paste with little water.
Add coconut oil to the clay pot. Once hot add turmeric and red chilly powder. This will give bright red color to the gravy. Mix well for few seconds. Then add soaked gambooge.
Transfer the gound paste to the clay pot. Add water as per the consistency you want. Check for salt. Add if needed. Mix well and let it boil. Then add fish pieces and lots of curry leaves. Cover and cook it for 10 minutes. Gently mix it once in between.
Once done, drizzles 1-2 tsp of coconut oil and more curry leaves. Cover and let it remain undisturbed untill you serve.