Chop onion, garlic, oregano, and olives.

In a small bowl add olive oil, lemon juice, salt, and pepper to chopped veggies.

You can use a food processor to chop and combine all marinated ingredients.

In a large bowl or large plastic bag, add fish and marinate for 30 minutes to 1 hour.

When time to cook, preheat oven to 350°F.

Place the fish in a greased oven proof pan/dish.

Bake 20 to 30 minutes until the fish flakes easily.