I've always heard that neons are not very hardy fish, but I've had nothing but great luck with them. They are just small fish, so you can't expect them to not be easily stressed. It's possible I've just always had captive-bred neons from good stock. Some might say that since they don't breed in my water it isn't ideal (Baseline pH of 7.8, kH around 7). I don't know, they still appear very healthy and live a full lifespan regardless. 8 dkH might be a bit high, I'm not really sure, but I wouldn't be afraid to try it. I think they would be fine as long as they are healthy to start with.