Speaking from experience. Have had multiple 8-12" indos, 7"-8" NGT in the same environment, and introduced a 2.5" indo and 2" Silver dat with no probs. I attached pics but can't see the little datters. They're in there.
Datnoids can be very aggressive between their own species I didn't know that smaller ones would be fine. But just to be safe I would keep feeding them.