Ok so for you situation, I would have a separate tank to isolate your new shrimps. Leave them in there for a week and monitor them. If everything looks fine then I'd put those amano's in your tank.
Thanks for the adviceAnother perspective is that invertebrates are generally more sensative to disease and dirty water, moreso than fish or other aquatic livestock. Amanos are hardier than all dwarf shrimp. Any signs of bacterial disease is visible by cloudy milkiness in their body. i'd avoid those cloudy looking shrimp if possible. Apart from that, you can also pickup one shrimp at a time, see how it goes and get another the following week just to stagger the impact. Your firereds are neos and they have been proven to be bulletproof. i'd be more concerned if they were any tibees or tigers... now those guys are real sensative...