it depends on when you add them, in what order. We have a pink watchmen that was our very first fish...he was in a 54g corner and down the line added a variety of other more aggressive fish including a Niger trigger and passer angel. Btw, the goby did not like the passer, one nasty jerk!!! Needless to say, we have upgraded everyone to a 180g dee-luxe apartment in the sky...and they have always gotten along. The goby is now a bit skeptical of the lunar wrasse we added a few weeks ago, but he is hanging out under a rock cave and comes out now and again.
In short, add the goby first and the trigger almost last in order of most peaceful to most aggressive and you should be ok.