Goldfish Velvet Disease

Goldfish Velvet Disease

Oödinium pilularis

Also know as: Gold Dust Disease, Rust, Velvet, Oödinium.

Goldfish velvet disease a common goldfish disease caused by the protozoan parasite similar to goldfish ich. The life cycle of the flagellate parasite includes a infection stage and a free stage. During the free stage, the parasites create a protective shell where divides and can create up to 300 spores. The hatched parasites can survive without a goldfish host for up to 24 hours but likely wouldn’t have to wait that long to find a host in a goldfish aquarium. During the infection stage the parasites attached and feed off the goldfish host. At first observation, the disease appears to look like the tiny white spots caused by ich but it eventually turns to a fine dusty gray or yellow color. The sick goldfish will then produce excessive mucus in attempt to fight off the disease, giving it a velvety appearance.

Symptoms of Velvet Disease

Early Stages

  • Rapid gill movement
  • Scratching and or flashing
  • Clamping of fins

Advanced Stages

  • A yellow-grayish dusting on the body
  • Excessive mucus production
  • Cloudy or protruding eyes
  • Ulcers and skin loss

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Casuses of Velvet Disease

Improper goldfish care and poor water conditions are a main cause for goldfish velvet disease; elevated levels ammonia and nitrite, or excessive nitrates. The parasites can be introduced when new goldfish are not quarantined or from cysts on aquatic plants.


A study showed goldfish exposed to velvet disease for 21 days, had a mortality rate of 88% while goldfish that had previously been cured of ich only had an 8% of mortality. (Dr. Y.M. Sin, Department of Zoology, National University of Singapore, 1999.) It’s not recommended to purposely infect a goldfish with ich to avoid velvet disease. Instead Quarantine new goldfish, disinfect aquatic plants and preform routine water changes.

Cure and Treatment

Salt baths are an ineffective cure for a sick goldfish with velvet disease; an ionic copper treatment, a free-form copper (chelated), is effective. Care must be taken to avoid an overdose of copper which can kill goldfish. Formalin is also an effective treatment for velvet disease. It too needs to be used with care to avoid burning the fins of the goldfish.

Reviewed By: Tim Winter

Tim Winter has a strong affection for pets and wildlife. His years of experience caring for various types of pets has led him to share his knowledge with others on the best practices in pet care. Tim holds a Bachelor of Science from the University of Oregon School of Journalism and Communications.

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