Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper for easy cleanup.
Pat the red snapper fillets completely dry with paper towels. This helps to achieve a better texture.
Place the red snapper fillets onto the prepared baking sheet. Drizzle evenly with olive oil.
In a small bowl, combine the minced garlic, chopped parsley, chopped dill, dried oregano, lemon juice, salt, pepper, and optional red pepper flakes. Mix well to create the herb marinade.
Spoon or brush the herb mixture evenly over the top of each red snapper fillet.
Arrange the thin lemon slices on top of the seasoned fillets.
Bake for 12-15 minutes, or until the fish is opaque and flakes easily with a fork. Cooking time will vary depending on the thickness of the fillets.
Remove from oven and let rest for a minute before serving.