Canned fish. Virtually everyone has one or more tins of fish in the pantry. It is so versatile and shelf stable protein can be handy in a crunch.
That said, I’ll do fresh as long as my local market has it.
No local fish mongers here. I had to do what amounted to a back alley drug deal to get some frozen catfish once at our grocery.
The stores don’t even have Oscar Meyer bologna today.