Velvet Disease

Velvet disease is caused by a parasite called Oodinium pilularis which is a parasitic skin flagellate. This velvet disease is also referred to as gold dust disease, Oodinium, and Rust disease. The Velvet disease is a common disease that is found in aquarium fishes. Although the name sounds good the disease is not that good for the fishes. Oodinium is the parasite that causes the velvet disease. This parasite is a dinoflagellate which is difficult to classify it as a plant or an animal. We all know that plants have the process photosynthesis and the animals move but plants do not move. This parasite has photosynthesis and it moves' That is why it is classified as a dinoflagellate. This parasite affects both fresh water and salt water fish.

The parasite that affects fresh water fish is called the Oodinium pilularis and the one that affects the marine fish is called the Oodinium ocellatum. The lifecycle of these parasites remain the same to that of another parasite called the Ichthyophthirius multifilis. The hook like structure that is found at one end of the parasite called the flagella is used to hang on to the host. Then this parasite enters the skin of the fish and eats up the tissues and grows. This destroys the tissues and the nutrients in the cells of the fish. After the parasite matures it drops off the fish and enters the stage of reproduction. At this stage it produces many parasites that swim in the water to find hosts to live on. The life of the parasite at the swimming stage is just a single day. Within this time it has to find another host or it will die. The parasite cause white spots in the skin of the fish which most often not noticed during the initial phase of the parasite.

Once the parasite infects the fish, the fish becomes irritated and starts to rub itself on the objects and the sides of the aquarium to get rid of that itchy feeling caused by the parasite. Sometimes the fish might be lethargic. The fish does not take the feeds properly when it is infected. Breathing becomes difficult and you can see the gill flapping faster than usual. You can find a rusty yellow color on the skin and the fins of the fish might be clamped on the fish. If you see peeling of the skin of the skin then the infection is in the advanced stage. The fins and the gills are mostly affected by the parasite.

For treating the fish the temperature of water in the tank is raised. It is better to switch off the lights or dim the light for a few days. Addition of aquarium salt might be better but make sure that cat fish is not there in the aquarium as aquarium salt might affect it. Treating the fish with copper sulphate solution for two weeks is a good option for the treatment of Velvet disease. The parasite is affected only at the free swimming stage so the treatment of velvet disease is aimed at eliminating the free swimming parasite. During the treatment carbon filtration should be avoided.