Some may think I'm dumb... but because of housing issues I had. My male checkered and a female okeetee corn together in a 36"x18"x 18" tank for several months before then introducing 2 albino checkered females. Only till shortly after adding the albinos did I notice the corn seemed stressed and at that time seperated her. Took her a month to git her back to her old self but now have a male for her.
I had no problems with them (same size) untill I added the other 2 females. So that's my experience.