they get big, easily couple feet, LFS has one prob close to 24" and i know they feed it shrimp and tilapia, and it does fine with aro, rtc, and some cichlids
at 11" i would say a 125gal but by the time he's grown a 180 at minimum.as for food it depends on what he's use to,if he's on feeders then you need to start there and move him onto other foods.massivore,shrimp,tilapia is what mine is on now.tank mates it depends on the fish himself but can try anything he cant eat but if like mine he has to live solo.
stop feeding him and once he is hungry enough he will start eating them but i would wait until he is settled in first so not to cause possible further stress .mine took missing 1 feeding but others i have heard taking a week sometimes more.massivore was the one mine took to best and now just loves them.