I have a question about Yellow Pyramid Butterflyfishs, (Hemitaurichthys polylepis). I have a 125 gallon, mixed reef. I have one Yellow Pyramid Butterflyfish in my tank for about 3 months now. I would like to add a second. Is this going to be an issue with the butterfly already in my tank? I have read out there on the web, that some sites says they do well as a single fish, others say, need to be kept in pairs/groups. I am looking for a little guidance from those who keep/kept these little guys. Thanks, for all of your replies. Cheers.