all you really need is a good algae scraper and a gravel vac. it's best not to rely on fish to do the cleaning for you. I know I have a pleco in my tank, but she's a lazy bum and doesn't take care of my algae really at all. in fact, she's better at trimming my java moss than doing anything else. I just have her in there because I happen to love plecos quite a lot.
not much is compatable with africans. i suggest getting a synodontis catfish, as they are from the same reigion as your cichlids. it may eat some leftover food, but you're still going to need to feed it and do gravel vacs and all that.