Biotoecus trouble

[Gillie]

I have what I thought was two adult female Biotoecus and things are changing. The largest one about 1 3/4" is definately a female stubbier bodied with an ever growing pink belly also becoming increasingly more aggressive toward the other, and the smaller one 1 1/2" had a pink sheen in the belly but has in the last month lost it and is now developing extensions in the pectoral fins, which seems odd to me as it did at one time have the pink belly. So my questions are could the smaller one be changing it's appearance to survive, could it possibly be a male coming into maturity or could it possibly have changed sex all together? I am also wondering that if no spawning takes place could the female become egg bound and die? absolutely all advice or insight would greatly be appreciated.