Totally Confused From Top To Bottom

I work at the fish counter in a grocery store.

Customer: “Give me the third one from the top.”

Me: “Which fish do you want? I can’t see where you’re pointing from here.”

Customer: “Salmon!”

I grab the third salmon from the top.

Customer: “TOP!”

I reach down at the bottom of the case.

Me: “You mean this one at the bottom?”

Customer: “I guess some would call that the bottom.”