I would suggest moving water over to it from your cycled tank instead. QTing them in an uncycled tank may actually make them sick, and kill them. Careful with that, those changes aren't going to help them much, and may make it worse since they're stressed already from a move. If you have a sponge, or I suggest getting one, put it in with your cycled filter for a couple days then move it to the QT tank, that'll cycle it. =)
As for food: Emerald Entree is a nice omnivorous diet(you can get that in the frozen sections at all pet shops that have a freezer, lot's do), I usually remove the worms. Fresh, blanched greens, some like cucumber and zucchini(boil it first, OR slice it, remove the seeds so they don't eat them and choke, and freeze them on a cookie sheet between wax paper, that's a good way of "Blanching" them). Minced up romaine lettuce, kale is good once or twice a week(you may as well boil that stuff, it's tough!). Blanch all fresh greens and give no canned foods. A boiled, skinned pea is good once a week. A nice high quality veggie flake food is good too. You'll only be wanting to feed them a very small amount maybe once a day while cycling, most would suggest less...but when so stressed making them hungry isn't gonna help but...it can up the bioload issue and add ammonia to the water feeding them more in an uncycled tank, once they're settled in a cycled area feed them twice a day so they aren't ravenous for their single meal(I found out they do better being fed 2-3 times per day, small amounts, they can get digestive issues with one feeding a day). x.x
