This is my 55 gal aquarium. Nitrogen cycled, water tests are good, aqua clear 110. I know it's messy. Once the fry get about an inch long I'm giving them and the father to my LFS. I didn't intend on breeding fish.
How many female convicts could I keep, comfortably?
A BN should be fine, and not a target for the convicts. If you're not keeping anything else in there, you could always try 5 females and rehome any trouble makers? Since there aren't any males for them to spawn with, you might not have issues, especially if you keep enough to disperse aggression. I would think it'd be worse to keep fewer than more. Maybe add some more rock hiding spaces, in the middle of the bottom of the tank and more in the upper regions of the tank, both to break the lines of sight and to give them space to make territories.