Algae Identification in Freshwater Tanks and Proper Removal

Owners of both freshwater aquariums and marine aquariums are concerned with algae. Algae has been around for billions of years, and new strains are still being discovered. It is estimated there may be over 37,000 species. Thankfully, not all these species grow in tanks, and some algae in small amounts are not a problem in aquariums.

Let us take a look at some of the most common types of freshwater algae that develop and ways you can eliminate them or keep them in check.

Black Brush Algae (BBA)
Black Brush Algae is a darker algae that may present itself on the equipment, décor, and slow growing plants in your tank. It resembles coarse horsehair and grows in dark tufts. It is notorious for its tenacity and ability to suffocate plants if left untreated. Coloration can range from blue green to olive to dark gray when young, maturing to a black color.

To rid your tank of this algae: Manual algae removal is the first line of defense. To prevent re-growth on equipment, it can be cleaned in a diluted bleach solution and rinsed well before being returned to the tank. Affected plants should be trimmed and aquascape should be cleaned and returned to the tank. A more natural approach is the introduction of Siamese Algae Eaters or Black Mollies into your tank (if compatible with other species present) to eliminate Black Brush Algae.

Blue-Green Algae or BGA (Cyanobacteria)
Even though it is considered algae, BGA is actually a bacteria that photosynthesizes like a plant. It is a slimy substance that usually grows in or on the substrate, and it can grow into thick sheets. Even though it is called Blue-Green Algae, they can come in these colors: blue green, bright green, greenish brown, brown, black, or even red. You will see this growth or smell it, as it has a pungent smell. This algae shows up in tanks that are well-lit and have warm, slow moving water with plenty of food and fish waste on which it feeds.

To rid your tank of this algae: This is a tough algae to get rid of, as it is invasive. You can manually remove from plants or prune them, scrub rocks, and vacuum the gravel. While you can purchase antibiotics to treat this form of algae, a first step may be to employ a blackout method to try to starve the algae of light, use a water conditioner, improve waterflow and avoid overfeeding your fish.

Brown Algae
Your first indication that this algae has made a home in your freshwater tank is a light brown to deep brown dusting on hard surfaces. If left unchecked, it can build to a thick layer. Brown algae tends to grow in environments with high silicate and phosphate levels that could be caused by extra food left in the tank or dead matter.

To rid your tank of this algae: Remove with your hand or a suction, wipe down hard surfaces, clean your gravel and make more often water changes. You can also use resins that absorb extra phosphates and silicates in your tank and reduce the level of light in your aquarium.

Algae eating fish such as herbivorous Plecos, Catfish or Snails will eagerly consume most forms of brown algae.

Green Hair Algae
Green Hair Algae looks like its name describes. You can identify this algae because it looks like hair strands on the edges of plants and rocks or a clump of hair that looks matted together. One of the contributors to this algae is an overabundance of nitrates and phosphates in your aquarium.

To rid your tank of this algae: Manually remove as much algae as you can, prune affected plants, increase your tank water changes to twice a week, and keep fish feeding low. Also, reducing light may help slow growth to a manageable level.

Green Spot Algae (GSA) and Green Dust Algae (GDA)
Green Spot Algae are typically identified as a growth of small dark green flat spots on glass surfaces or leaves of affected plants. Green Dust Algae usually appears on glass surfaces, and you are not likely to see it on rocks or plants. Causes for these algae include excessive lighting, low carbon dioxide or high phosphate levels.

To rid your tank of these algae: You can remove algae by pruning affected plants and scraping it off the aquarium’s surface. To prevent it from returning, you can reduce the amount of lighting in your tank or add Nerite snails, (if compatible with other species present) as they are effective in eliminating this type of algae.

Green Water
Green Water is a bloom that is caused when millions of single celled algae float on the water surface and is most likely caused by an abundance of light and food in your tank. Some tank owners do not mind a small amount of green water, as this algae consumes nitrogen and carbon dioxide and releases oxygen into the water. Also, some shrimp feed on microscopic green algae.

To rid your tank of this algae: Reduce the amount of lighting in your tank, avoid overfeeding fish, employ an effective filtration system, UV sterilization or add a Diatomaceous filter.

Staghorn Algae
Staghorn Algae is a form of Red Algae. You can identify this type of algae because it branches like deer antlers in stringy branched formations and is grayish green or grayish purple in color. They thrive in unstable environments and can be an indicator of a reduction in necessary tank maintenance.

To rid your tank of this algae: Manually remove as much algae as you can, trim old growth on live plants, decrease the amount of lighting in your freshwater tank, increase water changes and create water movement.

In Conclusion
When you maintain a freshwater tank, you may experience the presence of algae at one time or another. Do not let this deter you from fishkeeping, as there are many ways to address algae removal. There are also maintenance and stock feeding routines you can implement so the conditions are not present that enable algae to grow.