About a week ago, I bought some cod fillet at Costco. It had been packed the day before and IIRC, the sell by date was for 3 days later. When I opened the package to portion and freeze the cod (I didn't cook any just then), it smelled fishy. It had not been a hot day during transport and I have a fair amount of confidence in Costco's freshness. I have also smelled somewhat fishy fish that has been just fine once cooked. I do feel confident that that fish is safe to eat (firm texture, not slimy, no evidence of past its prime except smell).
I plan to defrost, rinse, and re-do the sniff test. If still OK, I'm thinking about doing in a cioppino to mitigate the smell. Any other ideas?
EDIT: If it still stinks after defrost and rinsing, I will toss it and have a little less confidence in Costco fish.