For the freshwater aquarist, algae outbreaks are practically inevitable. Outbreaks can arise due to a variety of issues, including light, water temperature, nutrient levels and water quality. Perform regular water changes, consistently test water conditions and chemistry, and consider using algae eaters to prevent outbreaks of these annoying autotrophic organisms.
Also known as blackbrush algae, red algae thrives in aquariums both acidic and alkaline in water condition. Red algae primarily grows on stationary plants and aquarium glass, and it can reach lengths of 3 millimeters. Remove red algae by discarding the plant leaves it resides on and by investing in a Siamese algae eater -- the only fish known to feed on red algae. Briefly dip fast-growing plants in a bleach solution and then rinse them well before adding them to your aquarium. These treated plants are resistant, although not impervious, to red algae.
Common to low-light aquariums and to aquariums with low nitrogen and high phosphate water conditions, brown algae quickly responds to an easy fix of strong, bright lighting. Brown algae, also known as diatoms, is easy to remove manually: simply wipe the notoriously weak and slimy structure from tank sides or tank paraphernalia. Acquire Siamese algae eaters, oto catfish or golden apple snails to keep brown algae in check and prevent its growth in low-light conditions.
Also known as green water, algal bloom is most commonly found in aquariums where algae growth has gone unchecked for a week or more. Algal bloom is full of microscopic unicellular green algae that reproduces rapidly in freshwater. Plenty of natural light, high nitrates and moderate to high ammonia levels add to ideal water conditions for algal bloom. The green algae also forms a slick lining on the inside of aquariums. Cycle standing water and neutralize the water conditions; the green algae will eventually dissipate.
Growing nearly a foot in length, thread algae is easily distinguishable by long strands that move freely in the tank water's current. Although pesky, thread algae is removable. Insert a clean toothbrush into the aquarium water, capture a few strands of the thread algae in the bristles and twirl the toothbrush to sweep up the remainder. The Siamese algae eater and Amano shrimp both feast on thread algae; lower iron levels and keep one of these aquatic creatures in the tank to prevent future outbreaks.