Water from an established tank wont do anything as all the bacteria that are beneficial are in the filter media. U need to start from scratch..get the tank out of the bathroom and cycle using media from an established tank. All those cories will die if that tank isnt cycled u wont just be "sacrificing" a few.
Not true.. In a cycled tank, everything is a bacteria host.. Gravel, decorations, glass, whatever..
Go to your LFS (not Wal-Mart!!!!!!! Never buy living animals from the same place you buy toilet paper..) and buy a few lbs of gravel from their tanks. Bring it home, break that tank down and replace the gravel. This will get you 90% of the way to cycled. The bacteria in the gravel will handle anything those cories can produce, and the rest of the tank will catch up within a couple weeks. If you can get filter media, that'll help too, but gravel is your best bet for a quick fix.