hey DBG, nice to see you here.. i don't think you need to put the NGT in a brackish setup, mine has been in fresh water all his life and is doing fine and about 10" now.. but i'd be really worried about keeping it with jardini's as i've heard they do not tolerate tankmates well and with a fish that expensive, i would think twice putting them together
NGT are beautiful fish and they have very nice gold yellow body when they get settled.. choose one that's always showing a nice gold color and bold black stripes