Listless, vomiting cat - plan visit to vets.
Hungry, bouncy cat with plenty of energy after ditching one meal - feed lightly (a little fish/chicken to start with and repeat if it stays down for an hour or two) and no worry. Exactly what everyone else has just said.
![Very Happy](images/smilies/icon_biggrin.gif)
Hasn't failed me yet.
Your own gut reaction is the best guide, though. You know him. If you feel in your heart of hearts (not the bit where you worry about being a good "mum") that he really is off colour or not well - get in touch with your vet. If you feel "wait and see" then do just that. "Fine, but keep an eye on" - you're very likely to be spot on with that one as well.