I never seen a RRS pass 7 inches in TL in captive aquaria.. but I mean who really knows right? Massive tank, crazy flow, balanced diet, and clean pristine water conditions possibly can get this beast to edge out pass 7in TL..
They can get up to 9in or possibly more but extremely rare. Like other serras they grow extremely slow, so for you to get him to that size you will need years plus optimal water conditions and diet. good luck!
It will be impossible to get a rrs to 9 inches unless you kept it for a long time and got it at 7 inches.....kind of like how almost all small rhoms brought in won't exceed 12 inches in captivity unless brought in at larger sizes
My largest rrs was almost 7.5 inches when I sold him 1.5 years ago
Not su much, I've tried to give the left over cichlids away, with no luck, so he has a healthy lunch to pick from.
He takes out the odd one, but for the most part he leaves them alone.