Combine yogurt, salt, garlic, grated ginger, mint leaves, coriander, cinnamon, cloves, and cardamom. Mix thoroughly and combine with fish. Set aside for 1 hour to marinate.
Grease a heavy casserole and alternate layers of rice, fish and tomato, ending with a layer of rice.
Sprinkle on melted butter. Cover tightly and seal casserole edges with aluminum foil.