They have problems with each other... like hamsters of different (certain) species can't be in the same cage or they'll fight each other. Like two male dwarf. But, I suggest you put the blue garomi in it's separate bowl. (:
Gouramis are more aggressive fish. They tend to nip at other fishes fins to show their dominance. Fish with long fins, like your angels, are their favorite targets. You can either separate them (which probably isn't what you want to do) or remove him temporarily, switch around the stuff in the tank, let your other fish get used to the "newer" environment and later reintroduce your gourami. Maybe that will help push him back down in the little hierarchy he decided.