If you want a suckermouth in your tank to help algae control then I highly recomend a Golden Dwarf Algae Eater. They are small and grow no larger than around 5-7cm. You will find them in your fish shop under the coldwater section. I have two reasonably large plain orange goldfish and they have both been living with my Golden Dwarf Alage Eater for atleast 2 years now. Sometimes the algae eater chases them off but not only is this very occasional but it only lasts a split second.