I want to paint the two top middle teeth so it matches the metal fangs but I can't find paint or markers that matches close enough.

Any suggestions?
I've tried a few silver and chrome markers which are close but still don't match that well.

 

Unfortunately, metal is metal and paint is paint. A paint that looks like real metal is kind of a holy grail. There are various chroming solutions but they vary in quality and they get really pricey for the better ones. Plus chrome is brighter than what you've got there.

For this, the closest I think you could achieve would be a brush on electroplating of nickel. Kind of a pain and a little on the pricey side and the drawback is you add several layers so you can start to lose some detail.