Funny you ask this question because I was just going to post a similar thread. I recently picked up some new fish in my smaller tank and they seemed to be flashing a lot. So I increased the temperature and added salt to kill whatever disease they might have. Just to make sure (in case I unwittingly contaminated my main tank) I also upped the temp in my main tank. Unfortunately my motaguense went crazy and started beating all her tankmates...I couldn't figure it out then I realized I raised the temp. Slowly I lowered the temp and now seem to have peace ... for the time being.
Bottom line, I agree with the other members here...lower temp = less aggression (but aggression does not goto zero)