Cook the rice till it is 80% done by adding in the ingredients listed under rice.
You can tie the masalas with a muslin cloth and remove it after the rice is cooked. Once cooked spread on a tray and allow to cool.
Marinate the fish with the ingredients listed and shallow fry them one minute on either side. Need not cook them all the way as it will be cooked in the sauce.
Fry onions listed under garnish in ghee till it is crispy and brown. Strain and keep aside. In the same pan fry cashew nuts till golden brown and raisins and keep aside.
Heat oil in a pan and add in crushed or finely chopped garlic, ginger, green chilly and mint leaves and fry for a minute.
Add crushed shallots and fry till golden brown. Add finely chopped tomatoes and saute till it is soft.
Now add in the turmeric powder, chilly powder and fry ( you can also add coriander powder - 1/2 tsp if you like).
Take one spoon full of this masala and mix into the yogurt and blend well. Now add this to the masala ( this will prevent it from curdling) .
Pour half a cup of hot water and stir well. Now add the fish pieces and cook in medium flame for three minutes.
Sprinkle little of coriander leaves and layer the rice on top of the fish masala. Garnish with coriander leaves,mint leaves, fried onion and cashews and drizzle a few drops of ghee. If you feel that the masala has dried up completely pour 1/3 cup of thin coconut milk finally on top of the rice.
This will add more flavor to the biryani, but this is optional. Close with a tight lid and place a little weight on top.
Cook in low flame ( or place a tawa first and then the biryani vessel) for four to five minutes. Serve warm with raitha, pickle and papad.