How to Control Fuzzy Red Blue-Green Algae

Fuzzy red algae growing in aquariums is most frequently some variety of blue-green algae. Blue-green algae is formed by diatoms, which are cyanobacteria that perform photosynthesis. This algae produces a slimy substance when it groups together in colonies and is notoriously difficult to get rid of. It is frequently a symptom of aquarium husbandry problems, including overcrowding and overfeeding. With proper aquarium maintenance, however, blue-green algae can be eliminated.

Things You'll Need

  • Peroxide
  • Air stone
  • Eye dropper
  • Algae scraper
  • Washcloth
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Instructions

    • 1

      Prevent the growth of blue-green algae by keeping the lights on in your aquarium for 10 to 12 hours each day. Overexposure to light, especially artificial UV light and sunlight, is the most common cause of algae overgrowth. You can also prevent blue-green algae by only feeding your fish as much food as they eat in 15 minutes.

    • 2

      Add oxygen to your tank by installing an air stone. Blue-green algae thrives in low-oxygen environments and is a symptom of a tank that has too little oxygen. Tanks that are overcrowded frequently suffer from low oxygen and the resultant algae growth.

    • 3

      Remove algae from aquarium ornaments and glass using an algae scraper or warm washcloth. Clean and change aquarium filters, which are frequently prime algae growth spots.

    • 4

      Drain your tank with an aquarium hose and completely change the water. This will remove any remaining algae floating in the water and lessen the likelihood of regrowth.

    • 5

      Treat blue-green algae with hydrogen peroxide. Use no more than 1 milliliter of peroxide for every five gallons of aquarium water. This treatment will only kill very small algae infestations and works best as a spot treatment. Treat algae growing on aquarium glass using an eye dropper, then wipe away any remaining algae. Hydrogen peroxide also works to prevent algae from growing back. If you've removed algae from your aquarium by changing aquarium water and cleaning the glass, treat the entire tank with hydrogen peroxide as a preventative measure.

    • 6

      Invest in a Siamese algae eater if you have a freshwater tank. These are one of the few algae eaters that will consume large quantities of fuzzy red blue-green algae.