For preparing seer fish/vanchiram/arkoli fish pollichathu, first mix together red chilly powder, lemon juice, turmeric powder and required salt with some coconut oil and apply the mixture on both sides of seer fish. Keep the fish pieces aside for a few minutes.
Heat some oil in a frying pan and fry ginger, garlic and onion to a golden brown color.
Add coccum water and little bit of water. Mix well and cover with a lid. Boil for a few minutes in low heat to drain off water.
Remove the lid and add coconutmilk. Cook again in low heat until the gravy acquires a thick consistency. Switch off the flame.
Take a banana leaf and brush the inside with some coconut oil. Apply the thick gravy on both sides of the marinated fish.
Roll up each fish in a piece of banana leaf and fry(pollikaan) both sides for 8 minutes in a hot tawa smeared with some oil.
Open the banana leaf and enjoy the splendid taste of seer fish/surmai fish/vanchiram/arkoli fish pollichathu. Serve hot with a piece of lime and onion slices.