One year later, the koi and the comet goldfish after today's big pond cleaning.
The one who started it all, Koichiro. He's grown to roughly 9-10" since I got him Halloween 2011. Notice that the orange blotch on his nose, the blotch that made me fall for him, has faded.

I then got Saiyo the sarassa comet goldfish on Valentine's, 2012. She's only 7-8" and hasn't grown much, which is a bit concerning.

Finally, around May 2012, I got Tanko from Petsmart. He is the biggest at 10-11" or so.
Considering that for much of the year, I battled nitrates as high as 80ppm and over in their pond, they look quite healthy. Koichiro, being a butterfly koi, has a bit of damage to his dorsal and his tail but it's clean and no signs of infection.