I have had a yellow candy hog for about 4 -5 years, originally started in a 90 gal, now has been in a 180 gal for about 2 years. This is an aggressive fish! ! Not peaceful like they say on many websites. My experience has been when I added him initially he was fine towards the existing fish, any fish I have tried to add since he made his home he bullies to death, only fish I have had success adding that he doesn't mess with are clowns and anthais. I don't think they will mess with much larger fish but haven't tried. But Any fish on the smaller side he will fight. It's been tough to find fish too add because of him. On the plus side it's a pretty fish and very active and a great eater and reef safe. Mine is probably 4 inches full grown. It also steals food out of the other fishes mouths if they don't swallow fast enough!