Preheat and prepare: Preheat the oven to 180°C. Sauté onion and garlic in olive oil.
Add okra and seasonings: Add the okra to the pan, followed by the white wine, curry powder, mustard, water, and lemon juice. Season with salt and pepper.
Prepare the fish: Cut the perch fillet into pieces, season with salt and olive oil.
Combine and bake: Transfer the okra mixture to an ovenproof dish. Place the fish on top and bake for 35 minutes. Then increase the temperature and bake for an additional 7 to 10 minutes until the fish is cooked.