Velvet (fish disease)

Parasitic disease affecting fish

Velvet disease is a common parasitic disease affecting freshwater and marine fish. It is caused by dinoflagellate parasites, primarily Piscinoodinium in freshwater and Amyloodinium in marine environments. The disease is characterized by a yellowish or gold dust-like appearance on the skin of infected fish, leading to its name "velvet."

Symptoms

Infected fish exhibit a range of symptoms, including:

• A fine yellow or gold dust on the skin, gills, and fins
• Lethargy and reduced activity
• Loss of appetite
• Respiratory distress
• Clamped fins
• Rubbing against objects in the tank

Causes

Velvet disease is caused by the parasitic dinoflagellates Piscinoodinium and Amyloodinium. These parasites attach to the skin and gills of fish, feeding on their host's cells. The disease is often triggered by poor water quality, stress, or the introduction of infected fish into an aquarium.

Diagnosis

Diagnosis of velvet disease is typically based on the observation of clinical signs and the characteristic "velvet" appearance. A microscopic examination of skin or gill scrapings can confirm the presence of the parasites.

Treatment

Treatment options for velvet disease include:

• Raising the water temperature to speed up the parasite's life cycle
• Adding aquarium salt to the water
• Using copper-based medications
• Reducing light exposure to inhibit the parasite's photosynthesis

Prevention

Preventive measures include maintaining good water quality, quarantining new fish before adding them to an aquarium, and minimizing stress factors for the fish.

Gallery

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  Betta fry, a species susceptible to velvet disease

• Fish showing signs of velvet infection

Related pages

• Ichthyophthirius multifiliis (Ich)
• Fish diseases and parasites
• Aquarium fish care

References

• Noga, E. J. (2010). Fish Disease: Diagnosis and Treatment. Wiley-Blackwell.
• Roberts, R. J. (2012). Fish Pathology. Wiley-Blackwell.

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  Velvet (fish disease)

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  Betta fry

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  Velvet infection