I got my first BTA a month or so ago and spent some time learning his likes/dislikes in a 10 gallon isolation tank with a clarkii. He likes having a place to dig his foot in so he feels safe and then opens out of that hole. He also doesn't seem to like much flow at all.
I actually just transferred the whole crew into my main display this weekend. I put him approximately where I wanted him to be. Definitely recommend turning off the powerheads at first. He ultimately let go, floated to the opposite side of the tank, attached to a rock, let go, floated back over to the original side, attached at the bottom of some rocks, then climbed up to where I originally wanted him to go. He then proceeded to dig his foot into an opening in the rockwork and has stayed put for about a day now. This was all with a clownfish inside along for the ride. Hehe.
Of course at some point you have to turn the powerheads back on and the resulting flow may or may not make them decide to move again. Although I guess once they've "dug in" maybe they'll be less likely to. Hopefully mine stays put. Good luck with yours!