Re: Different growth
I'd seperate them. these look quite young, not 5-6 moths like you say. The one in the photo is 3-4 months old i'd guess.
This is my terribilis mint offspring at 3months old to give you an idea :
Bastimentos,Citronella,Azureus,Hahneli,Patricia,Te rribilis,Escudo,Tumucumaque,Histrionica Bullseye.