I would go ahead and stock the CC now. Whereever you get them from nearby is gonna have warm water. Just make sure you acclimate them to your pond water by adding a little at a time to the bags or other transport container. I also wouldnt start off with any sinking food. That would do better as the surface temp gets too cold for them to surface feed. When that time comes, mix some in with the floating for the transition period. If you can get some of Cat's suggested feed, that would be ideal.