In order to get those stunning colors and tail displays you see on guppies at the fish store, you often have to breed two different guppy strains together. The offspring from these beauties are often not as colorfull or patterened as the adults. So the spare guppies that don't breed fancy, or the second or third generation from the fancy's don't show the same pure strain. They often get downgraded to feeder guppy status. So it's just like any other guppy, just not a geneticly pure strain with established crossing potential. If you get them in your tank and breed them, you'll get some random fancy's popping up now and then.
But it's all guppy,