I have had 2 clowns in the 55g for about 2 months now. They are a bonded pair and seem to get along. Last week, I added 1 yellow watchman golbie to the tank. Today one of the clownfish has been helping the golbie dig a little sand hole and they have been hanging out together in the hole. Do you think they are friends or is my clownfish trying to mark his territory or something?