The limited info I have found so far says they can max out at 12" but usually dont go past 6-8" in captivity.
No reports of them going after inverts or small fish, just warnings from sites selling them(might just be for CYA). Being a planktivore I wouldnt think it would be an issue.
Poor survival rates seem to be due to them not shipping well, or not eating on arrival but I dont see any actual info on how long anyone has kept one that was eating.\
I also found one video of an adult in a 400g reef as well which is a good sign.
And lastly I just got home and both of them are out and about and eating pellets.
Im gonna poke around and see if I can dig up any more info, but I might just keep them and see what happens.