In a medium bowl, whisk together apple cider vinegar, crushed garlic, and olive oil until well combined. Season with sea salt and ground pepper. Fold in capers, sliced red onion, and chopped parsley. Set aside.

Heat a large sauté pan over medium-high heat and add olive oil with a knob of butter. Swirl to melt and combine.

Pat fish fillets dry and season both sides with sea salt and ground pepper.

Place the seasoned fish in the hot pan, cook for 3-5 minutes until golden brown, then flip and cook for another 3-5 minutes until cooked through.

Transfer cooked fish to paper towel-lined plate to drain excess oil and let it rest for a minute.

Pour the herb dressing over the warm fish fillets just before serving.