At least in my local Petsmart, the employees have to sell a fish as what the shipping box says it is. Anything in the feeder tanks is a feeder and must be sold as such. I commented to a sales person that it was funny that there were sarasa comets in the $.27 tank that were as big as, and at least as pretty as the ones listed at $6.99 in a nearby tank. The cheapie I was buying was definitely prettier than any of the pricey ones.
She very confidently replied that they might look the same but they were "bred differently." The more expensive ones only got to be six inches long, while the cheapies got to be 12 inches long. I nearly choked trying to keep from laughing. But several of the people there have fish of their own and even try to talk customers out of putting their goldies in bowls or tiny tanks.
When I picked out a unusual goldie -- a copper-colored single-tailed fancy with huge flowing fins, I asked the sales person what she called it. The tank was labeled "calico ryukins / red and white orandas." She grinned and said, "Calico ryukin." I laughed and said, "Solid colored and with single tail?" She said, "I have to call them whatever the package says they are, even when it's wrong."
The difference between these two employees is that the first would have sold the koi without knowing the difference, and the second would have warned you that the fish was a koi and would need a big pond. She wouldn't have been able to transfer it to a koi tank or sell it as a koi.