Otocinclus, otherwise known as Oto cats or Otos, are small algae-eating fish that originate from South America. They are a great addition to any freshwater aquarium because they help keep the tank clean by eating algae off of the surfaces and decorations. While Otos can eat many types of algae, one type that they particularly enjoy is black beard algae (BBA). BBA is a slimy green/blackish algaefound on rocks and hard surfaces in aquariums and it can be difficult to remove without proper cleaning measures; however, with an army of Otocinclus in your tank you won’t have to worry about it! These little guys will do all the work for you – nibbling away at the BBA until there isn’t a trace left! In fact, if given enough time and food these fish could potentially get rid of most species of nuisance algae in your tank quickly. However, while these fish are good cleaners they should not be relied on solely for this purpose as overfeeding them could lead to other problems such as excess waste production which would then result in more unwanted nitrate levels.