Kos Maas Aru Bilahi Anja is a traditional Assamese fish curry made with river fish, mustard greens, and tomatoes. This flavorful curry is a popular dish in Assam and is known for its tangy and spicy taste. The fish is marinated with turmeric and salt, then cooked with mustard greens, tomatoes, and a blend of aromatic spices. It is best enjoyed with steamed rice.