Well from my personal experiance ( I have had it for about 1 year) my pbt is fine in my reef tank...but it has nibbled on a few corrals but that is just when I forget to feed it. It did eat my green stars frag and Bev's yellow buttons. It eats nori brine shimp and mysis and likes to nibble on krill if I strap some to her feeding rock
We got it at about the 3 " size or a little smaller but it is now about 4" tall and 6" long It loves the camera and will sit there a talk up a storm with you as you are at the tank. It is also an active swimmer and sleep behind the rocks at night. They have been know to get ick at a drop of a hat but I also have a cleaner goby in the tank and he keeps it in check
She did bug my 6 line when we put him in the tank but after a few days they we friends