Fish Curry with Okra

Name: Fish Curry with Okra
Ingredients: 1/4 cup vegetable oil; 1/2 teaspoon brown mustard seeds; 2 onions, thinly sliced; Kosher salt; 1 tablespoon grated fresh ginger; 4 cloves garlic, grated; 1/4 cup shredded unsweetened coconut; 1 teaspoon ground coriander; 1 teaspoon Kashmiri chili powder or hot paprika; 1/2 teaspoon ground turmeric; 3 small plum tomatoes, diced; 2 pounds monkfish fillets, cut into 2-inch chunks; Freshly ground pepper; 12 pieces okra, halved lengthwise; Cooked basmati rice, for serving; Chopped fresh cilantro, for topping