How to Remove Brown Algae From Fish & Plant Water

Brown algae, also known as diatoms, commonly develop in new tank setups. Usually seen within the first two to12 weeks of establishing fish and plant water aquariums, brown algae is not always considered bad. In fact, when it occurs in new tanks it often resolves itself once the water stabilizes. However, brown algae that appear in established fish and plant water may signify a variety of problems, including high nitrate and phosphate nutrient levels. The permanent removal of brown algae will require a combination of corrective and preventative measures.

Things You'll Need

  • Glass cleaner and scraper tool
  • Aquarium vacuum
  • Room temperature water
  • Brown algae-eating fish
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Instructions

    • 1

      Clean off all of the glass. A standard 18-inch glass cleaner and scraper tool should suffice. Vacuum the gravel or substrate on the bottom of the tank where brown algae hides with a small aquarium vacuum.

    • 2

      Perform regular water changes. At least once a month, siphon out the water in the tank with a standard aquarium siphon. Replace the siphoned water with room temperature water. Changing the water will dilute any excessive nitrates or phosphates that are feeding the brown algae.

    • 3

      Check the tank̵7;s lighting. A tank that harbors fish and plant life will begin to breed brown algae if placed in direct sunlight. If sunlight is not a problem, but you use fluorescent lights underneath the hood, assess how long you normally leave the lights on. Too little artificial light is just as bad as too much, so keep the lights on between 10 and 12 hours per day.

    • 4

      Monitor your fish feeding habits. Overfeeding your fish can result in an increase in nitrates in the water, especially if a lot of leftover food is littering the bottom of the tank. Feed your fish no more than two or three times per day, according to the label instructions on the food container.

    • 5

      Place some algae-eating fish in the water. While snails will usually eat the green algae in the tank, plecostomus, otocinclus and even some forms of sucker-mouth catfish thrive on brown algae. Each of these fish does a great job cleaning up the brown algae that resides on the glass, in the gravel and on the ornaments that decorate the tank.