In a mixing bowl, combine cherry tomatoes, Kalamata olives, red onion, capers, and parsley. Drizzle with olive oil and lemon juice. Season with salt and pepper, then mix gently.

Place a non-stick skillet over medium-high heat for about 2 minutes. Add olive oil and swirl to coat.

Pat the branzino fillets dry and season both sides with salt and pepper.

Lay the branzino fillets skin-side down in the hot skillet and cook for about 4 minutes.

Carefully flip each branzino fillet and cook for another 3 to 4 minutes until opaque.

Remove the fillets from the skillet and plate them. Spoon the relish over each fillet.