What are the symptoms of Freshwater Velvet?

A fine golden to rust-coloured dusting over the body rather than discrete white spots; The fish gasp at the surface and breathe rapidly, showing oxygen stress earlier than with ich; Clamped fins, darkened colour, heavy flashing and a tendency to sit in the filter flow; Progresses faster than ich, spreading from a few fish to the whole tank within days. It usually starts with: Pathogen introduced with unquarantined fish or plants; Long-term low oxygen and high organic load in an established tank; Outbreaks under low temperature or when the fish are already stressed.

How do you treat Freshwater Velvet?

In order: 1. Isolate at once and increase aeration (Velvet damages the gills and causes oxygen stress, so run strong aeration in the hospital tank and gather all affected fish into it.) 2. Change water and dim the light (Change 30-50% of the water with matched temperature and remove debris; Oodinium depends on light for part of its life cycle, so keeping the tank dark during treatment helps.) 3. Raise the temperature to 28-30 °C (Raise slowly to 28-30 °C and hold for at least 10 days. Velvet is more heat-sensitive than ich, but do not jump straight to the target.) 4. Salt bath from 0.3% (Add 3 g of non-iodised salt per litre in the hospital tank, halving it for sensitive species. Scaleless fish such as loaches, plecos and corydoras are sensitive to both salt and copper - use heat and water changes only for them.) 5. Copper or methylene blue in the hospital tank (Dose copper to the label and control it with a copper test kit for 10-14 days. Copper is lethal to corals, shrimp, snails and live rock life, so it belongs in the hospital tank only - never dose the display tank.) 6. Observe for 1-2 weeks during recovery (After the golden dusting clears, keep the fish isolated for another 1-2 weeks until breathing is normal before returning them, feeding lightly so water quality does not rebound.)

What medication treats Freshwater Velvet?

Copper sulfate / copper-based remedies: Hospital tank only, dosed to the label with a copper test kit for 10-14 days. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so treatment must happen in a hospital tank and never in the display tank.; Methylene blue: A gentler alternative used as a short bath in the hospital tank at the label dose. It affects plants and the biofilter, so change water and run activated carbon afterwards.; Quinine-based antiparasitics: Some products are labelled for velvet; use them in the hospital tank only, follow the label, keep them away from invertebrates, and never extrapolate a dose between brands.

G-04 / 02Freshwater

Freshwater Velvet丝绒病

Very urgent. It spreads faster than ich and can cover a tank within days; caught early the prognosis is good, but delay usually means discovering it after a mass die-off.

Illustration to come

G-04 / 02 · Freshwater Velvet

SpecificationsDisease atlas

Cause: Parasite
Severity: Severe
Contagion: Highly contagious
Corals / inverts: Not safe
Also known as: Oodinium、Gold dust disease

Symptoms

A fine golden to rust-coloured dusting over the body rather than discrete white spots
The fish gasp at the surface and breathe rapidly, showing oxygen stress earlier than with ich
Clamped fins, darkened colour, heavy flashing and a tendency to sit in the filter flow
Progresses faster than ich, spreading from a few fish to the whole tank within days

Typical triggers

— Pathogen introduced with unquarantined fish or plants
— Long-term low oxygen and high organic load in an established tank
— Outbreaks under low temperature or when the fish are already stressed

Treatment, in order

1 · IsolateIsolate at once and increase aerationVelvet damages the gills and causes oxygen stress, so run strong aeration in the hospital tank and gather all affected fish into it.
2 · Water changeChange water and dim the lightChange 30-50% of the water with matched temperature and remove debris; Oodinium depends on light for part of its life cycle, so keeping the tank dark during treatment helps.
3 · HeatRaise the temperature to 28-30 °CRaise slowly to 28-30 °C and hold for at least 10 days. Velvet is more heat-sensitive than ich, but do not jump straight to the target.
4 · SaltSalt bath from 0.3%Add 3 g of non-iodised salt per litre in the hospital tank, halving it for sensitive species. Scaleless fish such as loaches, plecos and corydoras are sensitive to both salt and copper - use heat and water changes only for them.
5 · MedicationCopper or methylene blue in the hospital tankDose copper to the label and control it with a copper test kit for 10-14 days. Copper is lethal to corals, shrimp, snails and live rock life, so it belongs in the hospital tank only - never dose the display tank.
6 · ObserveObserve for 1-2 weeks during recoveryAfter the golden dusting clears, keep the fish isolated for another 1-2 weeks until breathing is normal before returning them, feeding lightly so water quality does not rebound.

The standard treatment uses copper or formalin, which is lethal to corals, shrimp, snails and everything on live rock. Treat in a quarantine tank only, and leave the display tank fallow for the full period above before returning the fish.

Medications and cautions

Copper sulfate / copper-based remedies: Hospital tank only, dosed to the label with a copper test kit for 10-14 days. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so treatment must happen in a hospital tank and never in the display tank.
Methylene blue: A gentler alternative used as a short bath in the hospital tank at the label dose. It affects plants and the biofilter, so change water and run activated carbon afterwards.
Quinine-based antiparasitics: Some products are labelled for velvet; use them in the hospital tank only, follow the label, keep them away from invertebrates, and never extrapolate a dose between brands.

Prevention

Quarantine new fish for 2-4 weeks even when they look clean
Keep dissolved oxygen high, adding an extra airstone at night if needed
Control feeding volume and organic load, and clean filter pads regularly
Act as soon as a golden dusting appears instead of waiting for it to spread

Frequently asked questions

What are the symptoms of Freshwater Velvet?: A fine golden to rust-coloured dusting over the body rather than discrete white spots; The fish gasp at the surface and breathe rapidly, showing oxygen stress earlier than with ich; Clamped fins, darkened colour, heavy flashing and a tendency to sit in the filter flow; Progresses faster than ich, spreading from a few fish to the whole tank within days. It usually starts with: Pathogen introduced with unquarantined fish or plants; Long-term low oxygen and high organic load in an established tank; Outbreaks under low temperature or when the fish are already stressed.
How do you treat Freshwater Velvet?: In order: 1. Isolate at once and increase aeration (Velvet damages the gills and causes oxygen stress, so run strong aeration in the hospital tank and gather all affected fish into it.) 2. Change water and dim the light (Change 30-50% of the water with matched temperature and remove debris; Oodinium depends on light for part of its life cycle, so keeping the tank dark during treatment helps.) 3. Raise the temperature to 28-30 °C (Raise slowly to 28-30 °C and hold for at least 10 days. Velvet is more heat-sensitive than ich, but do not jump straight to the target.) 4. Salt bath from 0.3% (Add 3 g of non-iodised salt per litre in the hospital tank, halving it for sensitive species. Scaleless fish such as loaches, plecos and corydoras are sensitive to both salt and copper - use heat and water changes only for them.) 5. Copper or methylene blue in the hospital tank (Dose copper to the label and control it with a copper test kit for 10-14 days. Copper is lethal to corals, shrimp, snails and live rock life, so it belongs in the hospital tank only - never dose the display tank.) 6. Observe for 1-2 weeks during recovery (After the golden dusting clears, keep the fish isolated for another 1-2 weeks until breathing is normal before returning them, feeding lightly so water quality does not rebound.)
Is Freshwater Velvet contagious, and how urgent is it?: Contagion: highly contagious. Severity: severe. Cause: parasite. Very urgent. It spreads faster than ich and can cover a tank within days; caught early the prognosis is good, but delay usually means discovering it after a mass die-off.
What medication treats Freshwater Velvet?: Copper sulfate / copper-based remedies: Hospital tank only, dosed to the label with a copper test kit for 10-14 days. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so treatment must happen in a hospital tank and never in the display tank.; Methylene blue: A gentler alternative used as a short bath in the hospital tank at the label dose. It affects plants and the biofilter, so change water and run activated carbon afterwards.; Quinine-based antiparasitics: Some products are labelled for velvet; use them in the hospital tank only, follow the label, keep them away from invertebrates, and never extrapolate a dose between brands.
Is the treatment for Freshwater Velvet safe for corals and inverts?: No. The standard treatment (copper or formalin based) is lethal to corals, shrimp, snails and everything on live rock. Treat in a quarantine tank only, and leave the display tank fallow for the full period given above.