what kind of fish? how many fish are there in the tank? do you have lots of rockwork?
edit: i just checked your post on your tank, my guess owuld be the bumblebees are the ones being agressive? and mainly against the haps? dont know if this is so but i would think so, peacocks and haps should not be mixed with teh more agressive mbunas except electric yellows due to diet and agression differences, bumblebees are very agressive