Tropical Aquarium Fish Disorders

Tropical fish can become ill from a variety of disorders such as infections or parasites. Luckily, most disorders in a tropical aquarium are identifiable and treatable. Each type of fish has optimal environmental conditions, such as a target pH or temperature, that assist in prevention and treatment of health disorders. Many aquarium disorders are caused by poor water quality. Some disorders are wholly specific to one species of fish, such as Neon Tetra Disease. Medicating an aquarium requires specialist supervision because some medications can harm other fish, coral or plants in the aquarium.

  1. Symptoms of a Problem

    • Common signs of illness in aquarium fish include clamped fins, lethargy, loss of appetite, shimming in place, itching and spots or growths. Itching is frequently caused by a parasitic infection. Eyeball protrusion, commonly called pop-eye, is a general symptom of disorder as it can be caused by bacterial, viral or parasitic infections as well as a variety of other problems such as gas bubble disease, which is caused by nitrogen supersaturation from high-power air pumps.

    Bacterial Infection

    • Fin rot is a common bacterial infection from which fins appear shredded, tattered or decreasing in length. Dropsy is also a common bacterial disease in tropical aquariums and can infect the entire tank. According to the Flippers and Fins website, red blotches or streaks near pectoral fin bases are the first signs of the bacterial infection septicemia. Fish that become injured in a fight or by accidently scraping reefs are susceptible to infection at the injury site. Antibiotic treatments in the form of fish food will alleviate most bacterial infections.

    Parasitic Infections

    • Two common parasitic infections in tropical fish are relatively similar in symptoms and treatments; Ichthyophthirius multifiliis, commonly called ich, and Oodinium limneticum, commonly called velvet. Ich appears as white dots, sometimes raised, and velvet looks more like a white film covering the fish. Both infections cause fish to scratch against aquarium decorations or walls. Medicated treatments for ich and velvet are commercially available. Alternative treatments for these infections include feeding the fish garlic, adding salt, replacing the gravel or using cleaner fish.

    Fungal Infections

    • Fluffy or wispy growths on a fish are indicative of a fungal infection, which is usually caused by species of the fungi Saprolegnia. These infections are rare, as Saprolegnia prefer aquariums with stagnant water. Treatments for fungal infections are commercially available. Columnaris is a bacterial infection in saltwater fish that is often mistaken as a fungal infection and erroneously called mouth fungus.

    Viral Infections

    • According to Badman's Tropical Fish website, viral infections in fish often result in small tumors similar in appearance to miniature cauliflowers. These tumors frequently appear along the lateral lines of a fish or near the fins. Viral infections are more common in fish with a weakened immune system due to poor water quality, stress or other disorders. Tumors from viral infections can sometimes disappear on their own if the fish's immune system improves. Cancerous tumors can also be found in fish, which may or may not be surgically removed. According to the Aquarium Life website, viral infections in fish are rare.