Let the fish rest until it reaches room temperature.
Preheat skillet on medium heat.
Mix the spices together in a small dish or bowl.
Sprinkle spice mix evenly over the fish. You can also lay them out across a plate and roll the fish in it. The goal is simply to evenly coat the fish with a thin layer of spices. As long as the flesh doesn't directly touch the skillet, you have enough seasoning.
Add fish, one or two fillets at a time, to the skillet and cook for 2-3 minutes, or until the spices have begun to blacken and the fish begins to firm.
Flip the fish and cook another 2-3 minutes, or until the spices have begun to blacken and the fish flakes with a fork.If you have any question about whether your fish is cooked, official recommendations are to cook until an internal temperature of 145 degrees Fahrenheit. At this point the cod, much like a salmon, will begin to fall apart at the fat junctions and "flake" off of a fork. When you've done it enough times, you start to notice this particular type of firmness when the pieces ever-so-slightly begin to separate.