My apologies! In Calgary at least, we normally call Irridescent Sharks ID Sharks. The Emperor ID Shark is Pangasius sanitwongsei. I have read on some web sites that when these catfish grow, they often get fairly aggressive and seem to like biting the backs of RTCs for some reason. Mine only got to 15" before my 'accident' prompted me to get rid of it, but to that point, it didn't show any aggression at all.