In a bowl, combine olive oil, apple cider vinegar, crushed garlic, sea salt, ground pepper, capers, and sliced red onion. Stir until well blended.

Place a skillet over medium heat and add olive oil and butter. Let it heat until the butter melts.

Season the fish fillets with sea salt and ground pepper on both sides.

Cook the seasoned fillets in the skillet for about 4-5 minutes on each side until golden brown.

Transfer cooked fish to a serving plate and spoon over the caper and red onion dressing. Finish with chopped parsley.