I ordered sushi this evening from a reputable NYC sushi restaurant, where I generally find the fish to be quite good. I'm particular when it comes to fish, especially raw fish. When the sushi was delivered, over an hour later, I unwrapped it to find that the salmon, in my smoked salmon avocado roll, had a metallic, bluish glisten to it. I've seen this once before, but only after I left raw fish in the fridge one day too long. I was surprised to see this on smoked fish. Any ideas what the cause of this may be? I'm assuming it's indicative of something not very good.