Types of Freshwater Tank Algae

In a freshwater fish tank, many different kinds of algae can form. Each kind of algae has a different appearance, and each responds well to a different kind of removal system. Being able to identify what kind of algae you have in your tank will help you decide what is the most effective way to remove it.

  1. Green Algae Bloom

    • This algae is one of the most common to occur in the tank, and will turn your water a cloudy color. Because green algae blooms thrive in high levels of light, they can be combated with periods of darkness. Extensive filtering and sterilization also helps.

    Blue-Green Algae

    • This common algae grows in slimy sheets and has a strong scent. Periods of darkness, or blackouts, can help treat this algae problem. Erythromycin treatments can also help but may harm the fish in the tank.

    Brown Algae

    • Brown algae is a growth of brown spots on aquarium surfaces. This algae can be easily cleaned from the tank but also responds well to balancing out the nitrogen and phosphate levels in the water.

    Beard and Fuzz Algae

    • These algae, which both grow into a kind of short layer in the tank and are benign in small quantities, appear very similar. Beard algae grows in a thicker layer than fuzz algae. Algae-eating fish can keep these algae in check.

    Cladophora Algae

    • Cladophora algae looks like moss. Since this algae is slow to spread, the best way to get rid of it is to remove it from the tank by hand.

    Green Spot Algae

    • Green spot algae grows in small, hard circles on the walls of the tank. The best way to treat this algae is to raise carbon dioxide and phosphate levels.

    Black-Brush Algae

    • This is a hardy, moss-like algae which sometimes grows a lime tissue, making it unappetizing to algae-eating fish. Competition from aquarium plants and balanced nutrients should limit this algae.

    Green Dust Algae

    • Green dust algae forms in a slimy film across the glass of the tank. The best way to combat this algae is to let it grow into a thick layer. The layer will then fall off the glass and can be removed from the tank.

    Thread Algae

    • Thread algae grows in very long threads. Competition from aquarium plants and algae-eating fish will help to keep this algae in check.

    Hair Algae

    • This algae is similar to thread algae but grows in shorter strands. Hair algae is mostly benign, but many types of omnivorous and algae-eating fish will help to keep it under control.

    Staghorn Algae

    • Staghorn algae grows as branching threads. Balancing ammonia and carbon dioxide levels will help to eliminate this algae.