Hi Tong,
I have all my NTT on pellet and dry shrimp.
How long have you starved them? Do you have any other fishes with them or just them in the tank?
It's took me about 3 to 4 weeks. First I starved them for about 2 days, then I fed them with pellets. at first, they came up for food then stop, didn't touch the food. then I starved them for another 2 or 3 days, then tried again with pellets. It happened the same thing it happened the first time. I kept trying it for about a week and half or two weeks, finally 3 out of 6 taking pellets, the others 3 still not touching.
At that time I didn't want the 3 that not eating to die, so I fed them live blood worm for about 3 days, then I tried again. This time I tried with dry shrimps. After kept trying for about 4 times, all of them taking dry shrimps and then pellets. That is how I did it with my first group of NTT. (All died, after my 1 month vac. the outlet was short, kill all the power, so no air, heater and water cirl)
For the second group, I learned that it'll work faster if we have other fishes that fast eater and not shy with them in the same tank. I bought 2 mono and 2 red severum and put in the tank with 4 NTT and 2 IT and 1 ST. Fishes are followers. I got all of the dats eating pellets and dry shrimp except the ST (only dry shrimps.)
Good luck Tong.