I would QT them in the 58 till they are eating what you normally feed. Capt suggested to me a while back an anti-paracitic food that you can buy at most fish places for internal parasites. This is the biggest problem with anthis. It takes a while to get them to eat it, and then just follow directions for feeding them.
I would agree with reeffreak that once they are adjusted they are very active and aggressive feeders. My concern is when they are first introduced to the tank. After they settle in, they will jump in there with the best of them to get a chunk of mysis.
Let us know what you decide.