Place the fish, curry paste, cilantro, lime zest and juice, and egg in a food processor. Pulse until coarsely chopped. (Do not over mix to a paste. See Note.) Transfer the mixture to a bowl.
Cover and refrigerate for 1 hour to allow the flavours to meld.
Spread the panko on a plate. Line a baking sheet with parchment paper or plastic wrap. Lightly coat your hands with cold water. Shape 1/4–1/3 cup amounts of the fish mixture into small, 1" thick patties. Set the cakes on the panko as you go along; you should get 8 cakes. Coat the cakes in the panko, pressing it on to help it adhere. Set the finished cakes on the baking sheet.
Heat the oil in a large skillet set over medium to medium-high heat. Fry the cakes for 3–4 minutes per side, until golden brown and cooked through. Plate the cakes and garnish with lime slices. If desired, serve with mango chutney and yogurt for dipping.
Note: If you don't have a food processor, finely chop the fish on a board, place in a bowl, and mix in the other ingredients.
Note:Panko, Japanese-style breadcrumbs, is sold in the Asian foods aisle. The curry paste used in this recipe was Patak’s brand.