If it's a fairly new tank, it's best to avoid the Neons; they do best in a tank that's been cycled AND matured for a good 3/4 months, maybe more. The Neons we get these days are nowhere near the quality they used to be, ironically due to their popularity. Like a lot of fish now, they've been massively overbred and, as always, the quality usually suffers. Try having a word with your LFS and ask if you get something else for now, would they let you part exchange them for Neons a little later on when your tank is ready for them.