Heat a earthen pot or a heavy bottom pan with a lid, add sesame oil to it.
Next add mustard seeds, allow it to crackle, next add in fenugreek seeds, curry leaves, cumin seeds, fennel seeds one after the other.
Saute the ingredients for a minute or two and then add shallots or pearl onions, add salt and cook until the onions are slightly translucent.
Next add hand pounded garlic pods and saute into the onions.
Add in the pureed or finely chopped tomatoes and cook until the tomatoes turn dark reddish in color or until the raw smell is gone.
Add tamarind water to the onions and tomatoes once the tomatoes are cooked.
Add the spice powders mentions - Red chilli powder, cumin powder, pepper powder, fennel powder, turmeric powder and salt to taste.
Keep the flame on medium and bring it to a boil.
Once the curry comes to a boil, add the washed fish pieces one by one.
If you want you can adjust the flavour by adding a piece of jaggery and and cover the pot with a lid and keep on low to medium flame.
Simmer the fish kuzhambu for 10 minutes or until the fish is cooked and oil separates on top.
Serve it hot with Rice or idli or dosa.
