Mine is in a quite under-stocked 96"X30"X30" (375g), just him and his good buddy a 4.5" young Datnoid -- if there were more fish in there he might be more jumpy, I couldn't say, but so far (knock on wood) he has never demonstrated any jumping at all (and I leave the tank lid open for a good amount of time while cleaning or feeding). When I say he's skittish it's just once in a while and just for a second or two, and he just darts either way for a second, but not really up.
As RD mentions, they get pretty darn big and they grow quite fast (cuz they're eating all the time lol) -- I've personally never read about them slowing down after 7", not sure if this is true or not, will let you know as mine is just about 7" now but still growing like a weed.
I've had him about 4 months, since he was about 3.5", so nearly 1" per month growth rate up to now.