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Velvet Disease (Oodinium)

Affected fish

All fish.


Similar to whitespot, Oodinium is a parasite with a life cycle which involves stages on the fish, in the water, and in the substrate. The parasite attaches to the skin, gills, and fins, and causes irritation followed by inflammation and excess mucus production.


Affected fish may exhibit breathing difficulties, flicking, and reddened areas. Large infections produce a light dusting effect and a typical velvet appearance on the fish.


Quarantining and good husbandry are the only preventative measures.


Formaldehyde treatments are commonly used for velvet disease, and there are a number of proprietary treatments available. The disease has many hiding places and may re-emerge after treatment. Providing good conditions will help prevent further outbreaks.

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