Prep the fish: Pat fillets dry with paper towels. This helps the oil and spices stick and promotes a crisp finish.
Preheat the air fryer: Set to 400°F (200°C) for 3–5 minutes.
A hot basket prevents sticking and improves browning.
Mix the seasoning: In a small bowl, combine paprika, garlic powder, onion powder, salt, pepper, and cayenne if using. If you like a lemony finish, stir in lemon zest.
Oil and season: Rub the fish with olive oil on both sides. Sprinkle the seasoning evenly over the fillets, pressing gently so it adheres.
Prepare the basket: Lightly spray the air fryer basket with cooking spray.
Place the fillets in a single layer, leaving a little space between pieces. Work in batches if needed.
Air fry: Cook at 400°F (200°C) for 7–10 minutes, depending on thickness. Thinner tilapia may be done at 7 minutes; thicker cod could need 9–10 minutes.
The fish should flake easily with a fork and reach an internal temperature of 145°F (63°C).
Finish with lemon: Squeeze fresh lemon over the fish right after cooking. Garnish with chopped herbs if you like.
Serve: Pair with a simple salad, steamed rice, roasted potatoes, or air-fried green beans. Add extra lemon wedges at the table.