Do you see any indication of disease, other than hiding? Elevated breathing rates, spots on body or fins, white, stringy poop, head-shaking?
What's your water like? pH? Salinity, higher or lower than the water he was in previously? Is anyone else in the tank acting aggressively toward him?
Just trying to think of things that'll help folks on R2R help you and your trigger . . .
Triggers are rather intelligent fish, and he's probably a little freaked out by all the changes he's been through. That should pass within a few days or so, though . . .
~Bruce