I currently have my rhom in a 65 but I'm setting up my 250 and thinking about moving him in. I got him at 2.5inches 2yrs ago and he's 6.5inches now. I'm hoping he will have a growth spurt if I move him over to the larger tank.
I've seen more than type of fish have an immediate growth spurt when placed into a new larger tank. A good balanced diet that has good variety also helps tremendously. I've also had success with the high quality vitamin supplements that are around. Just remember... You get what you pay for, whether it's fishing lures,cars, or fish food/vitamin supplements. Thanks