I have had my Pink Tail for almost a year now and it still gets spooked if I venture too close to the tank. Some of the less "Agressive" trigger species (like your Bluethroat) can be very docile...
You can do like Rioreefer said, but I would just let the frozen cube float around the tank surface until it breaks up. The motion of the cube may get the Trigger's attention.
Also, if you haven't tried these already, frozen mussels, squid, beefheart and krill are usually trigger faves. You can get all 4 at most LFS'.
Edited by BobC63 - December 03 2009 at 6:17pm