christian, are they able to move all their fins? esp those in toward the posterior (back) of their body.
if they are, imo (mainly due to gut feeling rather than anything else) it's spine curve due to ammonia poisoning. i've seen it happen a lot of times in lfs. i've personally had some get it as well when i first started out. what you can do is to seperate them from the aro (as the rest have said), and ensure that they have VERY clean water.
if it really is spine curve, what you will need to do at this stage is to keep up the clean water, perhaps with 25% wc daily and if necessary, reduce the amount of food intake they have until their backs straighten (spine curve is curable, i've cured mine of it before). it's also a good idea to ensure that you don't spook them out; keep the lights off/dim, reduce or eliminate sudden movements around the tank, REMOVE THE JAR.
kudos for rescuing them from what would have been certain death at a lfs, but know that you have a long road of recovery to go through with these guys.
good luck