Six Line with Fairy Wrasse?

I was thinking about adding a six line wrasse to my tank with a 2" yellow fin fairy wrasse but then I know that some six lines can get aggressive so I thought since my fairy wrasse is such a little sissy it might not be a good idea to put another wrasse in? He has been in there for a few months along with a small maroon clown and firefish. Since these fish are already established would there be a problem adding a six line?

Ok thats what I was thinking too, so any other ideas for fish that will get along with what I have?