I have 7 dats in the grow out tank (75 Gallon). They were less than 1" long in December of 2007.
As of last night, they're all at 3.5"-4.5". Some of more dominants were the larger ones.
I feed them twice a day. Pellets in the morning, frozen foods at night (market shrimp, krill, silversides, smelt and smelt eggs)
I do WC 3 times a week at 35 gallon per WC.
Filtration: 2 - FX 5, Eheim 2217 and AC 110 (I did have 2, but had to take one out for hospital tank) I also have a lot of current in the tank, they love to hang out by the return stream and powerhead output.
In conclusion, keep them well fed, give them plenty of room to roam and swim, keep water condition in prisitine condition and you will have a fast growing dats.
stan