Heat oil in a kadai or deep pan over medium heat. Once the oil is hot, add mustard seeds, cumin seeds, fenugreek seeds, and asafoetida. Sauté this mixture for about a minute until the mustard seeds start to crackle.
Add the finely chopped tomatoes and salt. Cook the tomatoes until they turn soft and pulpy, approximately 3-4 minutes.
Add coriander powder, Kashmiri chili powder, turmeric powder, and ground cumin to the pan. Mix well and sauté the spices for about a minute to allow their flavors to develop.
Add the fish pieces to the masala mixture. Pour in the water and add tamarind paste along with the curry leaves. Stir everything together to combine the flavors. Bring the mixture to a gentle boil.
Cover the pan, and allow the curry to simmer for approximately 15 minutes or until the curry thickens and the fish is cooked through. Moreover, the fish should easily flake with a fork.
Once the curry reaches the desired consistency, turn off the heat and let the curry sit covered for 2 hours. This resting period allows the flavors to meld together, resulting in a more intense and delightful taste.
After the resting period, the Andhra Fish Curry is ready to be served. Additionally, serve this spicy fish curry hot with steamed rice or alongside traditional Indian bread like roti or naan.
