Tropical Fish Tank Diseases

Bright, exotic and graceful, tropical fish are a fascinating hobby and a beautiful addition to any room in your house. However, they may fall prey to one of the many common tropical fish tank diseases. Tropical fish are easily stressed and susceptible to disease. Be vigilant in checking your fish for signs of illness, particularly when you introduce new fish to your tank.

  1. White Spot Disease (Ich)

    • White spot disease, appropriately nicknamed Ich, is a common fish disease that often strikes in new aquariums. The parasite Ichthyophthirius causes Ich, burrowing into the fish's skin and feeding on its blood and epithelial cells

      Small white spots dot the fish head, body and fins. As the disease progresses, slimy gray patches may cover the fish. The fish will become lethargic and emaciated, and it will rub itself up against rocks or other objects in the aquarium as if trying to scratch itself.

      The parasite Ichthyophthirius is vulnerable to medication only during its free swimming phase, which typically lasts about three days. Once the parasite burrows into a fish it becomes insusceptible to chemical treatments. One parasite may produce over a thousand offspring, quickly infecting the entire tank.

      To treat Ich, raise your tank's temperature to 86 degrees Fahrenheit and treat the tank with trypaflavine or quinine for three weeks. Ich survivors seem to develop immunity to the disease but they can still carry the parasite and later infect non-immune new tank mates.

    Velvet Disease

    • Velvet disease is caused by a parasite called Oodinium pilularis and is capable of wiping out an entire tank. The disease is characterized by a fine gold film that covers the affected fish's body. The fish's gills may flare, and it will commonly gasp for air or rub itself against rocks.

      Oodinium lurks in many tanks, but only causes disease when the fish are under stress due to poor water quality, changes in temperature or transportation.

      To treat velvet disease, turn off your tank's lights and raise the temperature to 88 to 93 degrees Fahrenheit. Treat your fish with copper sulfate, trypaflavine, methylene blue or quinine hydrochloride. Some aquarium owners who prefer a non-chemical treatment report success with bathing the affected fish in salt water.

    Fin Rot

    • Early symptoms of fin rot include discoloring and fraying of the fins. Fin rot, as its name suggests, can eventually disintegrate the fins of infected fish.

      The disease most often is the result of accumulated bacteria and toxic compounds in the tank caused by improper water conditions.

      Purchase a good antibiotic from your pet store and check water conditions in your tank, correcting as needed. Permanent fin damage can be prevented by early treatment.