Why Do Goldfish Spin Themselves Around in Tanks?

Goldfish, like nearly any fish kept in a tank, swim back and forth across the tank, sometimes even swimming laps. When they're tired, goldfish often rest near the bottom of the tank among any vegetation that might be present there. In rare instances, however, your goldfish may move in an awkward manner, flipping or spinning itself in place. This could be a sign of swim bladder disorder.
  1. Swim Bladder Disorder

    • The swim bladder is the organ used by fish to keep their balance underwater. A deformed or diseased swim bladder means the goldfish is unable to stay balanced, causing the fish to sink to the bottom, rise to the surface, float upside down or even spin in place. One symptom of swim bladder disorder is a fish that stops eating.

    Genetic Problem

    • Goldfish, particularly those raised in pet stores, are the victims of generations of inbreeding. As a result, many of their internal organs, including swim bladders, are deformed. It is important to note, though, that if your fish has not displayed symptoms of swim bladder disorder in the past, the cause is not likely genetic and may be due to disease or diet.

    Dietary Problem

    • If the issue does not appear to be genetic in nature, stop feeding the fish for a few days. Then feed your goldfish steamed, skinless, crushed peas to cure constipation. It should begin to swim normally again; if it does not, the problem may be infectious.

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    Disease

    • If the problem appears to be disease-related, consult a veterinarian. Maracyn Two and Maracyn Plus are two medications commonly used to treat internal bacterial infections.

    High Nitrate Concentration

    • High levels of nitrate in the tank can cause symptoms that mimic swim bladder disorder. Make a habit of testing your tank regularly to make sure the symptoms your fish is exhibiting aren't due to nitrate poisoning.