I did know that neons are pretty sensitive, and I acclimated them over a period of about 2-3 hours, but I guess either that wasn't enough or there was something else wrong with them. As of now (2 days since I got them) there are still 2 neons left, so I guess I'll wait and see. I'm going to add a few more guppies this week, and if the neons make it, maybe I'll get a couple more to keep them company in a few weeks and try again.