My experience on this was completely different. When I got my first nem, I got it after about 6 months of my tank being up and running. I placed him in a bag and let him float, and i dropped some water in little by little every few minutes or so with a syringe. (I know, what a n00b)
After an hour, I put a little more water and then I placed him in the tank. Around 2 hours total. He stayed balled up for a while and bounced around my tank. After about 30 minutes he opened up just fine. The only issue I had was he moved around alot. He finally settled on my glass and opened up huge! After a year, he has grown at least 3 times in size.
He is the hardiest thing in my tank. Only him and my Diamond Watchman Goby survived my crash a few months ago. I love nems. Even though they move around alot, once they settle in they are great. Mine is getting too big for my tank so I need to move him on.