it needs a new tankmate as it's current one is sick

if the bristlenose that is staying is indeed a male, then i'd like it to be my alpha male so to speak, cos it's such a cool cat.. but he is young..
so, will he be okay hanging and growing up with a larger female? the lfs has larger stock that are sexed
if he turns out to be female later on, i've got plenty of space to bring in a mature male later..
thanks for any help
bristlehead