Cut fish into small pieces and grind fish and potatoes in a meat grinder on small grind. If grinder is not available use a food processor and pulse until the mixture resembles cornmeal. Heat the oil over medium heat and fry the onion until soft. Add the garlic, ginger, chilies, turmeric, coriander, garam masala, and chili powder. Stir and cook for 3 minutes. Add the cilantro and salt. Mix well and remove from heat.

Place the potato and fish mixture in a large bowl and fold in the onion mixture until well mixed. Cover the mixture and chill overnight. To make patties, use 1/3 cup mixture and shape into round shapes. For croquettes, use 2 tablespoons to form dough into croquettes.

Roll cakes or croquettes in flour, then dip in beaten egg and roll in bread crumbs. Heat oil in deep skillet and fry cakes until golden on both sides. Drain on paper towels. Serve warm or at room temperature.