In a mixing bowl or measuring cup, combine the avocado oil, lime zest, lime juice, minced garlic, chili powder, paprika, oregano, black pepper, and sea salt. Stir until well mixed.

Place the cod fillets in a sealable container or a zip lock bag. Pour the marinade over the fish, seal the bag or container, and gently shake or move it around to ensure the fillets are well-coated. Refrigerate for at least 30 minutes, or up to 10 hours for more flavor.

When you're ready to bake, preheat your oven to 400°F (200°C).

Transfer the marinated cod and all the marinade into a large casserole dish. Bake on the second rack from the top for 10-15 minutes, or until the fish is fully cooked. The cod is done when it reaches an internal temperature of 145°F (63°C). Using a digital thermometer for accuracy is highly recommended.

Serve the baked cod with your choice of side dishes. For a low-carb option, try pairing it with roasted asparagus and cauliflower rice, or enjoy it with lemon garlic rosemary rice.