I give two thumbs up to the nerites!!! I had a plexi tank that I couldn't scrape for fear of scratching and because it's small I didn't think about a pleco or anything but.............the nerite did an AWESOME job of cleaning!! I had tried wiping this algae off with a paper towel but that didn't do anything, so this was tuff algae and I was VERY impressed! PS I bought them from MSJINKZD