I purchased a small goldfish at the petstore recently. It's probably
about 2 inches in length. It has the triangular body build of a ryukin
or a fantail. Yet is has a single tail. It doesn't have the paired
tail fin that you see on most fancy goldfish.

Does anyone have any idea what it might be? I can tell that it not a
common goldfish or a comet by the shape of the body.