1. Heat grill to medium heat.
2. In a small bowl combine olive oil, chopped oregano, zest from 1 lemon and the juice from 1/2 a lemon, ground coriander, and salt then mix.
3. With kitchen shears cut away all the fins on the top, bottom and sides. Then cut 3 diagonal slashes on both sides and season with salt and pepper.
4. Place lemon slices and oregano sprigs inside the fish cavity and then place in a baking dish.
5. Coat the fish with the marinate and let stand for 15 minutes.
6. Coat the grill with olive oil to make sure the fish doesn't stick to the grill.
7. Place on grill for 12 to 14 minutes or until opaque.
8. Serve with olive oil and lemon wedges.