Season the cod: Pat the cod fillets dry with paper towels. Season both sides with salt and black pepper.
Sauté the aromatics: Heat cooking oil in a large skillet over medium heat. Add garlic, ginger, shallot, and red bell pepper. Sauté for 2–3 minutes until softened and fragrant.
Add the curry paste: Stir in the Thai red curry paste and cook for about 1 minute, stirring constantly.
Make the sauce: Add coconut milk, chicken broth, fish sauce, and sugar. Stir well and bring to a gentle simmer. Cook for 2–3 minutes.
Cook the cod: Carefully place the cod fillets into the curry sauce. Cover with a lid and simmer for 8–10 minutes, or until the fish is opaque and flakes easily with a fork.
Finish the curry: Turn off the heat and squeeze fresh lime juice over the curry. Taste and add more fish sauce, lime juice, or sugar if needed.
Garnish and serve: Top with Thai basil, cilantro, and chili. Serve hot over rice with extra lime wedges.