Bala's normally grow pretty fast IME with the right size tank, feeding and water changes, reaching in some cases 14-16".
I recently had four, which I got at approx 2", were 5" within 3 months before I rehomed them.
It depends on how your keeping them.
In good water and plenty of food i've seen them grow to 8" in as many months
I've also found 10" fish living in 24" tanks which is mad for these very active fish, which the owner said they was around 2 years old.
Bala's normally grow pretty fast IME with the right size tank, feeding and water changes, reaching in some cases 14-16".
I recently had four, which I got at approx 2", were 5" within 3 months before I rehomed them.
My girlfriend says they have grown but they look exactly the same to me. Could just be because I see them all the time so not really noticed. And I have 3 fully grown angels in the tank also so they look minute compared to them.