Hi some info from personal observations
mine went from 3" to 6" in two months.
i brought 5 home and lost 4 from ich with in a week (more prone to ich than bala sharks) And I never get ich!
the roseline sharks I own are very nipy/agressive keep my 3" congo tetras cowering in the corner. True barbs they are!
Here is a crapy pic of mine.
BTW guys my wholesaler is selling roselines for $5 each