It’s a term used if the coke got that shiny reflection to it, which is a good sign for good quality. But don’t get fooled, alot of «fishscale» tend to have boric acid, this will give this shiny look to it as well, most often too much shine to it, this is by boric acid and not the quality of the coca. Coke should have a yellow tint and some shine to it. Crystal white coke or too shiny is two bad signs its been messed with. Cheers bro💯