If you want some of the nicest looking fish that eat algea, get a plecostomus along the lines of a L44. Seriously but they are way too expensive I think. The zebra pleco is my favorite. Get one.
You could also get a knife fish if you want something interesting, but I don't know how it would get along with your cichlids... But they defenetly are fun to watch. An Elephant nose would be pretty strange too.
Or if you want fun ditch all the fish you have now and get discus and live plants. Or go reef.