At what size do you start to see aggression?

[Fish Eat Fish]

I have 9 dragons blood peacocks (3 males) and so far I have very little aggression, certainly nothing to be concerned about. That being said they are only 2.5 inches or so in size. I never really got into Africans so this is new to me. When should I expect to see issues that I may need to deal with?

 

[DJRansome]

Another half inch, or when they color up, or when they start spawning...all about the same time.

 

[Fish Eat Fish]

Thanks just want to be ready