Take the fish out of the refrigerator and place on a plate or sheet pan. Rub with salt and Greek seasoning. Set aside.
Drain capers and roughly chop. Mince garlic.
In a pan large enough to hold fish in one layer, melt the butter. Add the garlic, lemon juice, lemon zest, and capers and bring to a simmer. Cook for 30 seconds, then add the fish fillets. Simmer for about 7 minutes, depending upon the thickness of the fish. While cooking, use a spoon to scoop the butter mixture on top of the fish (basting). Once the fish is cooked, sprinkle with parsley and serve.