Surprised you have difficulty finding them- everywhere I look has them... even Walmart (not that I'd buy from Walmart).
You could always ask if they plan on keeping them in stock- I know from talking to a Petsmart employee here that they get more fish in starting in autumn through until Xmas than they carry the rest of the year...
... maybe they're starting to carry their Xmas stock extra early and your store doesn't normally carry them... dunno- but I know they're in Walmart, SuperPetz, Both Petsmarts, and the LFS in my town... maybe their availability just varies region to region... dunno.