I have only found p-bass to be especially prone to ick when newly introduced to a tank. Now that I think of it I have never had ick on any of my bass after a week of owning them.
yea you may get ich and prob will when you fist introduce your peacocks but then it fades if the water conditions are correct higher temp does always help..
87-88F and higher they will not really get ick.. also a uv sterilizer will help.. but honestly a cichla can get ick at any size if they are weak. i feel 6 inches are still a bit to small so around 9-10 inch they a bit stronger