I have been experimenting with my heidi in the fridge lately. I have ben able to keep them in the fridge for a week or more w no adverse affects. Sometimes my heidi produce way more than I can use, so I put the extras in a culture cup w excelsior in the fridge. It keeps them alive, but slows them so much that they don't gas themselves. I have even started new cultures with heidi that have been in the fridge for almost a week and didn't notice any difference in production. I have put producing cultures in the fridge (just to see what happens), and the maggots don't seem to make it much more than a week.
I have put about an inch of flies in a cup in the fridge, and didn't have the best #'s survive, but when I added excelsior, they did much better because they aren't smothering themselves.
I was just wasting flies before, so I figured why not try something, they were going down the toilet anyways?
Mike