Hi...yeppir, it was me that Ky Kim was talking about and I decided to drop by to tell you that they do very well in my pond.
I have four and they are very docile...the koi brush past them and they just go with it. Someone once told me that they stay on the bottom, and that's not true at all with mine. They have come to the top, and they've ventured all over the pond and even swam around with the other fish from time to time. They don't get to the sinking pellets fast enough, so all I can do is see if they survive on the algae and other 'stuff' on the bottom, and so far they have.
I've seen a few larger ones and they were about $70 for a 10-12 inch hi-fin, so the link was pretty close to what I paid locally...then you have shipping to contend with. I was told they like to be in groups of three or more, however, I rarely see all four of mine in the same place.
These pictures are at the shallow end of the pond...so they're definitely not stuck to the deep parts of the pond.
These smaller ones that I got in Calif were about $25 for a pair. They are slow growers, but will get to about 24-30 inches in larger ponds, and they also lose their high dorsal fin when they get older.