A group of thorichthys aureaus, helleri or socolofi would be my choice.1 male and 6 or 7 females would work very well.They would not be too aggressive and would breed kept this way.
You could also add a group of livebearers like swordtails. or if you wanted something a little different for the top levels, the pike top livebearer would be an interesting addition.
You could also add a group of livebearers like swordtails. or if you wanted something a little different for the top levels, the pike top livebearer would be an interesting addition.