Syno cat... not sure what species but their are a few that specialize in predating cichlid fry/eggs/nests. or a predetory pleco may also be the ticket.. depending if you've got mouth breeders or egg layers.. I'de look into some form of fry predetor that will leave the adults but take care of the fry or at least help control it.
P.S Otherwise i think CR's idea just might work... It works for me.