This is the General Aquaria section and your thread is on Dats, so a better place to get info. from those who like keeping Dats is in MFK's Datnoid section. Since that's the appropriate section and I believe you'll get better answers I have moved your thread to the Datnoid section.
As for what to feed your Dats, the first thing I'd try are sinking pellets; as that's the best diet for them. How ever Dats can be slow to take to pellets and you may have to resort to feeding frozen or live. So if the Dats have never eaten pellets which at their current size is most likely and they refuse the pellets offered you can try cut pieces of shrimp or fish. If they refuse that blood worms or small guppies should get them eating. Once they're established and eating well then you can try breaking them onto pellets again.