Personally I think its all about how well they're fed in the first year or two but thats just my opinion. I've had my regal since 2005 and he was about 5" when I got him from a fellow reefer. He's maybe 7" now he eats like a pig.
Contrast that with the orange shoulder tang I got this past March (no idea on age, I got it from the LFS and it had juvenile colors). It was about 4" when I got it and is now approaching the size of the regal, that is some crazy fast growth and yes, he also eats like a pig
