Filleting Blue Cod – the Traditional Way! There are plenty of ways to fillet a blue cod, but this is the method I prefer. No pulling, no tearing of the fillets or skin — just clean cuts that keep the fillet intact and bone-free. This fish was bled and gutted straight after capture, then left on ice overnight to let the rigor mortis process complete — the result? A clean, firm fillet that’s a dream to work with and a pleasure to eat. Notice how effective cutting the gill membrane is for bleeding