Currently Im keeping a G.Smithii with a true perc clown and they seem to get along fine. This is probably mostly due to two aspects: the clowns like hanging out close to the surface and are not too nosy around the tank, and the G.Smithii isent, by a long shot, the most aggressive stomatopod around. They are both in a ten gallon, with mushrooms, xenia, star polyps etc. basically anything I dont want im my main reef tank anymore.
Cheers,
Brian