I think maybe you should give him a week-ish with the company then draw your thoughts. I don't typically just fire employees on the spot because they make mistakes like that. I train them, if training doesn't work, then we can talk about firing, point being, making all your assumptions after someone is with the company for one day isn't really the right way to go about it.
Also I want to be clear here, I am neither on Rectrox's or Kloxified's side on this one. This is just my honest opinion im writing here.