I saw this post and wanted to add a thought. I have some tangs in my tank, not sure if you are looking for that type of fish but they eat algae like nothing I've seen before. I bought a tank from a store that was closing about a month ago, very established, beautiful, but full of hair algae and algae on the walls. After a few weeks I added some tangs to the mix and it was crazy! They ate and ate, every bit of it was gone in like 3 days, I couldn't believe it! I have other tanks that are too small for tangs and use other cleaners (snails, crabs, etc.-all good too) and they have never done anything like that before. If your tank is too small for tangs (short or small in g) try a foxface they are also great algae eaters and very colorful fish.