What are some small species of mouth brooding cichlid that aren't hyper aggressive? Like some that I could put in with a Ctenopoma to keep population under control?
Some of my favorite small mouth brooders are Alcolapia alcalicus.
They top out around 4", the males have nice color, none aggressive.
They are endemic to Lake Natron in Africa, tolerate temps in the nineties, and react well to saline conditions if needed for disease treatment.