The first year generally sees the most growth, I got my first dat last October at 1.5" and today he is approx 4" but most of that growth came within the last 3 months. If you get one up to 6" in the first year you did pretty damn good. You usually get less growth each year though that's not set in stone depending on diet, tank size, w/c's etc.
Alright well then what should I feed him? The fish handler at the store said he was already eating pellets but I highly doubt that as he was feeding the fish blackworms and left.
depends on the type of datnoid u have ur ST, IT, NTT, NGT, and AT so depending on what u want, and what size could range from prolly $200-$2000 would be my guess