Marine Fish Disease Symptoms

Marine fish diseases are common to saltwater aquariums and the fish that inhabit them. The symptoms of a sick fish will vary depending on the actual disease it has acquired. Avoid marine diseases by reducing the amount of stress aquarium fish experience. Good, clean water at the proper temperature is essential to preventing disease, as is the recreation of a fish's natural environment and proper diet. Understanding different disease symptoms is essential to know when your fish are ill.

  1. Fin Rot

    • Rotting of the fins that creates an appearance of missing fins or jagged fins is the primary symptom of fin rot. The fins look like they are falling off. Severe fin rot can infect a fish's skin, which is signified by bleeding.

    Ulcer Disease

    • Caused by vibriobacteria that grow in dirty, overcrowded water, ulcer disease is an internal infection that has several external symptoms associated with the disease. Lethargy, loose scales, darkening color and ulcers on the skin or jaw are some of the most obvious symptoms. Other symptoms that generally indicate the disease has advanced beyond the early stages include bleeding of the gills or pale gills and bleeding through the skin and internal bleeding in the intestinal track.

    Cauliflower (Lymphocystis)

    • Indicated by white, wart-like lesions on the fish's skin and fins, cauliflower is a viral infection that will usually resolve itself. It is, however, easily transferred between fishes. It may take several weeks before the lesions caused by this infection grow to full size.

    Whirling Disease

    • Whirling disease, caused by the ichthyophonus fungus, is very serious. This disease infects internal organs of fish including the kidneys and heart. Symptoms include the appearance of being malnourished despite plenty of food, a change in color, skin ulcers, roughening appearance or feel to the skin, erosion of the fins and a curving of the spine. This disease usually results in death; however, once it is diagnosed, infected fish should be separated from healthy fish as the disease spreads fairly easily.

    Marine Velvet Symptoms

    • Marine velvet is a parasitic infection that affects the texture and appearance of fish skin. It begins in the gills and then spreads to the rest of the body. The skin becomes patchy, with white spots on healthy parts of skin and other areas of skin simply looking dull in appearance and texture. Other symptoms include scratching on aquarium decorations, gasping for air and a lack of interest in food. The disease has no known treatment, results in death to the infected fish and requires a thorough cleaning of the aquarium.

    Tang Turbellarian Disease

    • Also known as black spot, this disease is caused by paravortex flatworms. Symptoms include black spots anywhere on the body, sluggishness, pale skin or scratching. Although the name implies that this disease is unique to the tang fish, the assumption is incorrect. Many different fish can be infected, especially in an aquarium. Infected fish need to be treated and isolated to avoid spreading the disease.