Preheat oven to 375°F.
Add grapeseed oil to a sauté pan over medium-high heat. Season fish with salt and pepper and sear on both sides until golden brown.
Across bottom of a casserole dish, arrange tomatoes, fennel, garlic, thyme, oregano, capers, potatoes, and olives. Place fish on top.
Slightly cover fish with vegetables. Ladle olives over fish and place in oven. Allow to cook for 15–20 minutes, or until fish is done and vegetables have slightly caramelized.
Take dish out of oven and drain off most of the oil. Garnish with parsley and serve family-style.