Rinse the swai fish fillets with cold water and pat dry with paper towels. Season both sides with salt and ground black pepper.
Place a large skillet over medium-high heat. Add the vegetable oil and wait for it to start sizzling. Pan-fry the fillets, about 1-2 minutes per side, or until light brown. Transfer to a plate.
To the same pan, add the butter and melt it, then add garlic and ginger, stir and cook for 30 seconds.
Add capers, lemon juice, parsley, red pepper flakes, and a pinch of salt. As soon as the sauce starts to bubble, turn off the heat.
Return the fish to the pan with the sauce and drizzle it on top with a spoon, garnish with lemon wedges and parsley.
Serve immediately.
