To be very honest, any fish that "cleans" is also going to contribute to the problem with their waste... so really the only thing is to tackle the problem thats causing the algae in the first place...
For example, is your tank close to a window with a lot of direct sunlight? are you possibly over-feeding? Is there left over food in the tank? Are you maybe not doing enough water changes? Maybe you need some live plants to out compete with the algae...
Coz when i started out as a fish keeper i thought having something to "clean" the algae would be great, only to realize later on that there is no real quick fix to the problem since you have to tackle the problem at the root of the cause... Honestly, the only reason i have my current pleco was coz a friend of mine bought two and gave one to me... otherwise, i would never add a pleco to one of my tanks unless i was actually into plecos...
Oh and last but not least, even with an algae eating fish, they won't clear up all the spots, so at the end of the day, you will still need to manually get at the algae for a really clean tank...