not posted in a while but thought i would on this topic.
This is a story my dad always tells about undjualted trigger fish, it his favorite fish also by the way. we actually currently have one in a tank by himself anyway here is the story:
when my dad first got into the hobby before i was born about 25-30 yrs ago
he had a achlies tang a lion fish and undjulated. he had them together for over a year.
one day he woke up, the lion fish had his spines eaten off, and the achlies was laying at the bottom of the tank with his eyes eaten out. The fish just snapped he tried to put a naso tang with the fish a few wks later. while the fish was in the bag the undjualted tried to attack it. so he had to take it back. My point is eventually the fish might just snap, im not saying he will but its like a rattlesnake you just dont know. anyhow good luck.