If you get algae, you can control it with algae-eating fish like otos. Plecos can work as well, but most are for large tanks (55g+) & put out a lot of waste (dwarf plecos can work in tanks smaller than 55g). Apple or Mystery snails (big waste producers) can work as well, depending on tank size & what kind of fish you have. Ghost shrimp can be used too if you have no fish that would eat them.YodI said:I saw a photo of an aquarium that was just taken over with green algae! I'm a beginner and don't have my fish In the tank yet. How do you control the algae? Do you need special chemicals or something like that? I don't want a green tank!