It is a bit overstocked. Don't forget things will get worse as the fish grow.
Do you know how old the neons are? When they get old the grow paler, move a lot less and tend to look a bit tatty. As many people buy them as a group, chances are they are all the same age so when one dies, the others aren't often far behind so people think they have something wrong when in fact it is geriatric siblings.