What's this fish? Some kind of rainbow?

Just went by Petsmart. I was checking out their tanks, and when I checked the X-ray tetra tank I noticed something odd. This definitely isn't an X-ray tetra. It has two dorsal fins, for one thing. It doesn't look like anything on any of their tank lables. It's shaped sort of like my forktail rainbows, but it's bigger... Any clue what it is? It's around two inches long. For size comparison, that's an actual X-ray tetra near it.
And yes, I bought it. I figure that whatever it is, it should do fine in my 65g... Doesn't look like anything I know of that's large or mean or difficult.
However, if anyone in Austin or Georgetown wants it...