Algae growth is inevitable. As one of the biggest challenges for aquarists, the trick is to keep it in check to ensure the health and safety of your fish tank. To maintain algae that serves your aquarium environment but without it growing excessively, let’s dive into the the causes of algae growth and how to properly maintain it effectively.
Types of Algae
Before you can control the presence of algae in your tank, you’ll need to know which type you are dealing with. Here are the most common forms:
Gravel or silica aka “Brown Algae”
This form of brown algae is common in new tank environments. It typically shows up by coating your tank in sheets that you can wipe off. This form of algae growth is harmless and will disappear as soon as your tank acclimates. As it is soft, it can be easily controlled with time or the use of clean-up crews who love to snack on it.
Slime or Smear Blue-Green Algae
This bluish-toned algae lookalike is actually not an algae at all. Instead, it is a cyanobacteria that is attributed to water with excessive nitrates or phosphates. This slimy blanket type of algae can be reduced with regular aquarium cleaning and improved air circulation. If you are experiencing a large amount of blue-green algae in your tank, you can introduce an aquatic-safe UV Light to reduce the number of cyanobacteria or lower the amount of time your tank light is on.
Green Spot Algae
This green form of algae is pretty common and is harmless as long as it does not overrun your tank. As small, hard green spots on the surface of the walls, it can be caused by many things including too much light, an imbalance of phosphate or low CO2 levels. We recommend manually removing this form of algae growth with gloves or an algae scrapper before it spreads to your plants.
Black Beard Algae
One of the more stubborn forms of algae, this red form often appears on plants with a high stock of fish. This form of algae growth is commonly formed through high organic water pollution and lack of water changes. To rid your tank of this algae, remove the affected area from your tank environment and use a mix of water and a small amount of hydrogen peroxide to gently wipe it off.
Tips to Maintaining Algae Growth
To avoid algae overgrowth, reduce the lighting in your tank and be sure to move away from any direct sunlight. You may also want to reconsider the amount of food that you feed your fish as excess food in water can increase the phosphate levels. At Hikari®, we also recommend changing ten to fifteen percent of your tank’s water every week in addition to testing your water source to watch for any levels of ammonia and nitrites during your weekly water tests. Adding live plants can also help combat growth as they absorb the nitrites into nitrates.
Last but not least, supply your tank with algae-eating plants and fish to reduce nutrients and counter algae overgrowth. Freshwater species such as Siamese algae eaters, Otocinclus catfish, and nerite snails are just a few of the many species that can help reduce the amount of algae in your fish tank. Contrary to belief, adding plecostomuses may not always help reduce the amount of algae in your tank, as they can often produce heavy waste and might grow fairly large. For tanks under 60 gallons, try adding a Bristlenose Pleco or the Rubber Lip Pleco, as they are peaceful and graze on algae and biofilm throughout the day. Keep in mind that they will also need to be fed more than just algae. ®Hikari’s sinking Algae Wafers™ alongside blanched vegetables and protein sources are essential to ensure they have a well-rounded diet.
Final Thoughts
Controlling algae growth can be maintained with a combination of good fish-keeping practices, including proper feeding, regular cleanings, and balanced lighting. Through regular maintenance you can keep your aquarium clean and visually appealing for you and your aquatic pets.

