Preheat your oven to 375°F and lightly oil a baking dish.
In a skillet, heat olive oil over medium heat. Add garlic and onion, cooking until fragrant.
Stir in curry paste, then pour in coconut milk. Let it simmer for 5 minutes until creamy.
Add sliced bell pepper and season with salt and pepper.
Place cod fillets in the baking dish and pour the curry sauce over the top.
Bake for 18-20 minutes, until the fish flakes easily with a fork.
Squeeze lime juice over the top and sprinkle with fresh cilantro before serving.