I have had Dats eating freeze dried krill (pieces or whole) the day after I got them, I think they are attracted to the scent of the shrimp. Depending on the size of the fish, you could put a few common tetras (like Black Skirts) in with the Dat, when it sees them eating prepared food it make take the hint. I did this will my small 2" Dat, adding 5 Black Skirts and now the Dat is eating Tetramin flakes!!! I added the flakes to fill up the tetras bellies and then added pieces of freeze dried krill for the Dat but I guess he couldn't wait! In my case the tetras were added because the Dat spent so much time in hiding. Have other active fish made him feel more confident and now he is out all the time.