Marius is probably correct. No one messes with this guy, the tank is actually quite peaceful. However, when he was his normal, active self, whenever i put food in the tank he ate WAY more than anyone else. He was just way faster than the frontosa.
I think that i was just too slow in treating him. I noticed/thought that he was acting oddly and that something was wrong, but I didn't act right away... partially because i didn't know what to do and what exactly to look for.
Thanks for everyones help and suggestions though. The good news is that i learned alot about tropheus and how to look for and treat bloat.