Velvet

Symptoms

Early recognition is the key to a good outcome, so inspect your fish daily at feeding time. A fine gold/rust dust over the skin (best seen with a torch), flashing, clamped fins, rapid gill movement and lethargy. If you notice several of these signs together, act promptly rather than waiting.

Causes

A dinoflagellate parasite, often introduced with new fish and triggered by stress and poor conditions. In almost all cases the underlying trigger is stress, poor water quality or the introduction of an infected fish, all of which weaken a fish's natural defences.

Treatment

Dim the lights (the parasite is partly photosynthetic), raise temperature slightly, and treat with copper-based or proprietary velvet medication for the full course. Remove invertebrates and carbon during treatment.

Throughout treatment, increase aeration, remove activated carbon from the filter (it absorbs medication), complete the full course even after symptoms fade, and keep the water immaculate with regular changes. Always follow the medication's dosing instructions and dose for the tank's true water volume.

Prevention

Quarantine new arrivals and maintain stable, clean water with minimal stress. The golden rules are simple: quarantine every new fish for 2-4 weeks, never overstock or overfeed, avoid sudden temperature or chemistry swings, and perform regular partial water changes. A stable, clean, low-stress aquarium prevents the overwhelming majority of disease outbreaks.

FAQ

This information is general guidance, not veterinary advice. Consult an aquatic vet for serious cases.