I currently have 3 PJs in a 55gallon, I'd like to get some more to fill out the space since the only other fish that are own in the open are 2 clowns and a royal gramma. I thought I remembered reading somewhere that they need to be in a group of odd numbers otherwise they'll bully one to death, is that true or am I misremembering/thinking of another fish? How many should I stock in a 55gallon? Bioload isn't an issue, currently at 1ppm nitrate.