Also I would rearrange his tank before adding the female to disturb his established domain. Unless you want multiple females, I'd only buy one at a time and have the 100 as a back up. I had a large aggressive male midas, and I found he did quite well with a smaller female that I added at a later point. I didn't divide them, but I did provide a clay pot for her with an opening the male could not fit through...Good luck and these fish reproduce like crazy in my experience