Where k3vin is located is not listed, and maybe things are different in the UK, Tokis, but here in the US neons are rather hardy in the great scheme of things. They are commerically bred in the very alkaline waters of Florida -- very different from their native Amazonian waters. Conversely, most cardinals are still wild caught, so they will not be nearly as readily accepting of as wide range of water. Part of the problem is that neons must be bred in mass in order to be profitable, so there has been some inbreeding in the lines. Massive breeding has led to the fish being far more susceptable to neon tetra disease, for example. But you can always ask your LFS how the batch has been doing, or find a local breeder to purchase from.