Types of Algae on Aquarium Glass

There are few things more agitating to aquarists who devote their time to creating the perfect aquarium than a curtain of algae covering the glass. Many aquarists do not understand that algae are a natural part of any aquarium and its presences is not something to battle, but rather an element to manage. There are many species of algae that thrive under various aquarium conditions. Identifying the type of algae is the first step to successfully managing it in your aquarium.

  1. Green Spot Algae

    • Green spot algae is one of the most common forms of algae found on aquarium glass, and can be one of the more difficult to remove. The small, hard, circular green spots usually form under high-light conditions. Algae eating fish do not help control this type of algae because of its hard structure. If green spot algae become too prevalent in a tank they can be removed manually. In glass aquariums a razor blade is the best method to remove unwanted algae. While in an acrylic tank an acrylic-safe algae pad and a lot of elbow grease is the safest way to remove green spot algae without scratching your tank. Frequent water changes can help prevent the appearance of large amounts of green spot algae.

    Green Dust Algae

    • Green dust algae usually forms on the glass of aquariums in large, soft clusters of growth. They are a common type of algae that can arise in new tanks or well established tanks and are a source of headache for many aquarists. Green dust algae is actually a free-floating stage of algae development called a zoospore stage. And though green dust algae is easily wiped off the glass of aquariums, but manually removing the algae from the glass will not fully remove it from the tank since many of the free-floating zoospores will remain, only temporarily clean the glass. The best method is actually to let the algae grow. Often, this will result in the algae completely covering your tank so that you cannot even see inside. In two to three weeks however, the bloom will diminish and change to a dark green or black color. At this stage, the algae can be removed and should not return.

    Thread Algae and Hair Algae

    • Thread and hair algae appear as long, filamentous strands of algae. Thread algae can grow to much longer lengths than hair algae, but they have a similar structure and are sometime found growing together. Thought they usually form at the base of aquatic plants, on substrate, or other hard objects in the tank, they can root themselves in small scratches on aquarium glass. Excess iron in the tank can be a possible reason of the appearance of these algae, but some aquarists actually welcome their appearance. Many omnivorous and herbivorous species of fish will readily feed on both types of algae. Their presence should be monitored carefully however, as a large volume of these types of algae can entangle fish. Both types are easily removed by twirling a toothbrush around them.

    Brown Algae

    • Unlike most algae, brown algae usually appear in aquarium environments with low-lighting conditions. The soft, brown clumps can appear on hard surfaces in aquariums, such as glass or on the substrate. The presence of brown algae usually indicate a high concentration of silicates in addition to low levels of light. Brown algae are easily removed by wiping them off the glass or siphoning the substrate. Increasing the amount of lighting in the aquarium can help remove brown algae and prevent future outbreaks.