Preheat oven to 400 degrees F.
Place veggies on [url:1]baking sheet[/url] and drizzle with 2 tablespoons olive oil. Sprinkle with salt and pepper, mix, and then push to the sides of the pan.
In a [url:2]small bowl[/url], mix remaining 2 tablespoons olive oil, lemon juice, garlic, parsley, red pepper flakes, and onion powder together. Place tilapia on pan between the veggies and rub the marinade on all sides of the fillets. Sprinkle tilapia with salt and pepper.
Bake for 12-15 minutes or until fish reaches 145 degrees F and flakes easily. Serve immediately with rice, pasta, or quinoa.