Heat oil in a pan.
Add fenugreek seeds and let it splutter.
Add garlic and ginger and stir for a minute.
Add green chillies and stir lightly.
Add the onions and sautT until translucent and glossy.
Add turmeric powder and stir well.
Add fish and the third extract of coconut milk.
Bring it to a boil. Lower the heat and simmer, turning carefully once, for 3 mins.
Add salt and stir well.
Add curry leaves, tomatoes and the second extract.
Cover and simmer for 3 mins.
Remove the pan from heat and gently (to make sure that the fillets do not break) stir-in the first extract of coconut milk.
Return the pan to heat and bring to a boil over low heat.
Sprinkle lemon juice and stir carefully.
Remove from heat and adjust the seasoning.