Fungus Growth in an Aquarium

Fungus growth has a cotton-like appearance and can be easily identified. It typically forms on tank debris, driftwood or leftover food in the aquarium. In many cases, the fungi anchor in areas that are not well-maintained or cleaned regularly. Fish living in aquariums with fungal growths are prone to illnesses, infections, skin lesions and various other health problems.

  1. Causes of Fungal Growth

    • Organic wastes and dirt are the primary reasons for fungal growth. Fish fungus also forms spontaneously due to unhygienic conditions in the aquarium. Using untreated driftwood in tanks can lead to fungus formation in an aquarium. Generally, fungal and bacterial growth in fish tanks occurs simultaneously.

    False Fungus and True Fungus

    • White tuft cotton-like formation or discoloration on the mouth of the fish is called mouth fungus. Similarly, other parts of the body like fins and tails have white patches and these are called fin and tail rot fungus, respectively. The rotting of fins is quite even and the appearance of a white edging or a line indicates that the fish is infected. In the chronic form of the disease, these markings are light gray and mostly appear on the mouth of the fish and have a cotton-wool appearance which people often mistake as fungal infections when they are bacterial infections. Hence, they are called false fungi.

      False fungal disease is caused by bacterium called Flexibacter columnaris, and the disease is known as columnaris disease. False fungal infections have a grainier and coarser appearance and look more like ulcers. True fungus have a white, cottony appearance. It develops in tanks due to poorly aerated water, rotting fish food in the water, filter and substrate, and unhygienic water conditions.

    Treating Fish Fungus

    • There are anti-fungal medications especially formulated for fish. Many people use preparations containing erythromycin or phenoxyethanol to combat fungal growth in aquariums. If you are using a biological filter, it can get damaged due to these antibiotics. Hence, change the filter. Also, monitor the nitrite and ammonia levels after the treatment, as high levels are harmful for the fish.

    Precautions

    • Introduce just the required amount of food into the tank, so that the food does not accumulate at the bottom, providing an ideal breeding ground for fungi and bacteria. Remove excess food regularly. During the cleaning process, remove one-third of the water from the tank. Use gravel cleaner to thoroughly clean the substrate. Clean the bottom and walls of the tank thoroughly to get rid of fungal growth.