If your grilling a lot of fish we recommend cooking only 4 to 6 fillets at a time. Too many fillets will end up breaking out of the foil wraps and be difficult to manage on the grill. Best to cook multiple foil wraps if you have a lot of fish to be cooked. Also recommend cooking your favorite veggies and and potatoes in foils wraps separate from your fish. This allows focus on each item individually to properly cook.