Signs Of Infection

Fish rub against hard objects. A yellowish-gray film consisting of tiny spots appears on the fish's body. The fish may also show signs of increased respiration and loss of appetite.

Fish Affected

All aquarium fish are vulnerable particularly fry.

Details Of Infection

Caused by the parasite Oodinium pillularis. This parasite follows a similar life cycle to White Spot (Ich). The parasite attach themselves to a host fish where they feed and grow. As they mature, the parasite falls from the fish and develops into cysts encased in a membrane on the substrate. Here the cyst divides forming 64 new cells within 4 days where upon the membrane bursts freeing the cells into the aquarium to find a new host. If the cells fail to fin a host within 24 hours, the cell dies.

Velvet usually only arises when poor aquarium conditions prevail and is highly infectious.

Treatment

Increasing the temperature to 82°F and application of a commercial chemical treatment containing copper is most effective. Dimming the aquarium lighting and subjecting the affected fish to a strong (3%) salt bath also aids recovery. It is worth treating for up to one week after all signs of velvet are removed from the aquarium to ensure that mature parasites have been discharged from the fish and developing cysts are eradicated from the substrate.