Heat the oven to 350 F. Lightly coat a 9-by-13-inch baking pan with cooking spray.
In a small bowl, combine the tomato, basil, oregano and garlic. Add the olive oil and mix well.
Arrange the halibut fillets in the baking pan. Spoon the tomato mixture over the fish. Place in the oven and bake until the fish is opaque throughout when tested with the tip of a knife, about 10 to 15 minutes.
Transfer to individual plates and serve immediately.