I'm not sure if I got lucky with breaking my Dat's or it's because they're different species than yours but I'll tell you what worked for me. I've got AT's and a IT and all where eating only live on arrival. I bought a hang on breeding box and filled it with rosy reds, predictably the Dat's hovered around the bottom of the box incessantly trying to eat the reds. This accomplished 2 things it got the Dat's out of hiding on a regular basis and willing to think of food as coming from the surface of the water rather than the bottom and mid water stalking they're used to.
After a week I attempted to feed the reds by hand to the Dat's. They took it after my third attempt that day and ran into hiding to finish eating them. Within a week they where no longer striking at the breeder box anymore but where always close to the front of the tank hovering in the general area and observing me as much as the feeders. When I approached the tank they'd get riled up swimming back and forth quickly while in a head up position waiting for me to feed them the reds. They where associating me with food so I attempted cut shrimp strips stuffed with Hikari cichlid pellets.
They where hesitant but the other fish in the tank attempting to consume it must have convinced them it was alright so on my first attempt they where feeding on the shrimp. I normally feed my little cichlid grow outs flakes and pellets, the flakes are taken from my hand pellets eaten as they sink. Before I knew it all 3 of the AT's where eating flakes and pellets but the IT still will only eat shrimp from my hand. Hopefully he'll eventually be broken on to flakes and pellets all in all the breaking off live took 2 and 1/2 weeks for me and all Dat's are stable and very out going I believe as a result of the handfeeding and constant initial temptation of the feeders. They became more comfortable in the open at least that's my opinion on what transpired. Maybe you can attempt the same and hopefully get similar results. Hope this help's though I've never kept NTT's so don't know how finicky they can be.
