Bluegreen Algae Aquarium Cure

Blue-green algae, termed cyanobacteria, is bacteria that photosynthesizes. Cyanobacteria gives the aquarium a dirty appearance and smothers aquatic plant life. Blue-green algae also releases toxins, which affect fish negatively. Although blue-green algae typically occurs in newly established systems, it can appear in mature aquariums that are poorly managed. Dirty filters and pieces of uneaten food allow blue-green algae to become easily established.

  1. Physical Eradication

    • Blue-green algae should initially be physically removed by hand. Blue-green algae forms thick mats on the aquarium substrate, rocks and décor. Rocks and décor can easily be removed and cleaned. A hard bristled brush will remove cyanobactera from these items, which should then be rinsed under running water before being returned to the aquarium. Blue-green algae may also coat filter pipes and power heads and these items can normally also be removed for cleaning. Blue-green algae is typically resistant to eradication and the aquarist will need to repeat the cleaning process more than once.

    Water Changes and Siphoning

    • Blue-green algae mats that are covering the substrate can also be siphoned out of the aquarium. The process of siphoning removes large amounts of the cyanobacteria and has the added advantage of allowing the aquarist to replace old water, which has a high organic load, with fresh water. Water will be siphoned from the aquarium together with the mats of blue-green algae and, in this way, metabolic waste material in the aquarium water is diluted. It may be necessary to repeat this process every two or three days until the cyanobacteria has been eradicated.

    Increased Filtration and Aeration

    • Cyanobacteria grows best in environments that are poorly aerated and where circulation is low. Aquarists should clean their filters and pumps and ensure that this equipment is functioning optimally. Additional air stones can be added to the aquarium to increase aeration and aquarists must strive to achieve near-saturation levels of oxygen in the water. The exhaust nozzles of power heads and other filters must be directed into the corners of the aquarium, to eliminate potential stagnant areas. In cases where the blue-green algae is particularly resistant to control, a second filter may need to be incorporated on the aquarium.

    Limit Live Stock and Food

    • Blue-green algae thrives in an environment with high nutrients. Fish release metabolic waste into the aquarium on an ongoing basis. This waste comprises feces and urine and encourages elevated levels of both phosphates and nitrates in the aquarium. The more fish an aquarium contains, the higher the metabolic load will be. Overstocked aquariums are typically also overfed because of the large number of individual fish. Uneaten food is frequently found in these aquariums and blue-green algae thrives under these conditions.