How to Make It
Stir together celery salt, thyme, cayenne, and 1½ teaspoons pepper in a small bowl. Rub 1 tablespoon oil all over fish fillets and sprinkle evenly with pepper mixture. Let stand 5 minutes.
Meanwhile, stir together peaches, onion, tomatoes, cilantro, honey, kosher salt, lime juice, 1 tablespoon oil, and remaining ¼ teaspoon pepper. Set aside.
Heat remaining 3 tablespoons oil in a large skillet over high; add fish and cook, undisturbed, until charred on 1 side, about 3 minutes. Flip and cook until fish flakes easily with a fork, about 3 minutes.
Serve fish with peach-tomato salad, with lime wedges on the side.