Toss the tomatoes with 3 tablespoons olive oil and lay on a parchment lined baking sheet. Bake for 15 minutes, until tomatoes have blistered slightly. Remove from oven and turn heat down to 375.
Lay the fish filets on another baking sheet and season with salt and pepper. Drizzle with remaining olive oil and lemon juice, and bake for 10 minutes, until fish flakes easily with a fork.
Serve the fish topped with the roasted tomatoes and sprinkled with fresh chopped basil.