How do you avoid algae build up in an aquarium?
Algae is the bane of many an aquarist. It grows. We remove it. It grows back, and then we remove it again. In spite of our tenuous relationship with the algae in our aquariums, we cannot escape the fact that without algae, none of us would be here! Photosynthetic algae and cyanobacteria produce the majority of the Earth’s oxygen supply, and if those algae ever die . . . SO DO WE!
Algae are mostly-photosynthetic organisms that sometimes resemble plants but are not plants, having no true roots, stems or leaves. Algae grow in freshwater and saltwater. Saltwater algae are sometimes referred to as “seaweed.” Like plants, algae require light and nutrients to grow. We supply plenty of both in our aquariums, with several hours of aquarium lighting a day and nutrients like nitrates and phosphates from fish waste.
Algae come in many forms. There are microscopic, one-celled algae, filamentous algae that resemble hair, algae that grow in sheets, and macroalgae that look like plants. There are even algae that live inside the outer integument (“skin”) or calcium shell of some corals, anemones, and other sessile invertebrates called zooxanthellae. There are slimy-looking algae that are often not algae at all, but a colony of primitive photosynthetic organisms known as cyanobacteria. There are also very hard-to-remove little dots of green that sometimes grow on aquarium panels which also are not algae, but diatom or radiolarian colonies (microscopic, one-celled, animals with hard shells) with algae incorporated in their matrix. With all that said, let us answer some common questions right up front:
Algae growth is inevitable in an aquarium.
Algae consume nutrients in the aquarium that if allowed to accumulate, are harmful to fish. Algae can be a good thing.
The presence of green algae in an aquarium indicates a healthy environment for fish.
There is absolutely no way to completely prevent algae from growing in an aquarium, without killing the other life in the tank.
Chemicals should never be used to control the growth of true algae in an aquarium, and should only be used in rare circumstances to control cyanobacteria.
Correcting a severe algae problem requires time and patience.
Natural methods of controlling algae are the best and most effective.
Algae removal from the tank panels can be done on an as-needed basis, but no more than once a week. Removing algae involves either correcting negative water conditions to control or slow excessive algae growth, or an age-old process known as “elbow grease” (scrubbing it off!). Algae removal in an aquarium should be done only when necessary. We have seen many aquariums where daily removal of algae resulted in fish that were so stressed, most had diseases and were dying. You should never remove all of the algae from your tank. Allowing some algae to grow in the aquarium can be beneficial to the aquatic environment. When algae is removed from aquarium side panels, care should be taken to select an algae scrubber that will not hurt the finish of an aquarium. Be careful not to get gravel caught in an algae scrubbing pad where it can scratch the aquarium. Never use household cleaning pads to remove algae. They contain fungicides that kill fish.