I keep Canadian nightcrawlers alive for months too in the same box. I keep them in the upper refrigerator door which is a little warmer than the other places in the refrigerator.
mine are up high in the frig as well and been there a month and checked on them after I read the post ....
they been to the water twice already and all of them look right ready to go hit it again .....
wonder how long they were in the box before i bought them is me
If you know of a gardening buddy borrow a cup or 2 of Pure Canadian Sphagnum Peat. Wet a couple of tablespoons for a few hours then mix it in with the old box soil. Before you add you'll have to remove that much old soil.