The Aquarium and Pond Active Online Publication

Lymphocystis Virus

Emperor Angelfish with a bad case of Lymphocystis.

By Tony Griffitts

Lymphocystis is a common iridovirus disease seen most often in the aquarium hobby on marine angelfish and butterfly fish.  The classic sign a fish has the virus is the white cottony looking patches normally at the edges of the fins, but also can appear on the body.  The disease some times appears in freshwater fish in the aquarium hobby, but far less frequently.  The disease is rarely fatal and normally the white tuffs of enlarged cells will disappear on their own in time.  It is believed that the virus is spread by physical contact.  There is no treatment for the disease.  Once the fish have had the disease they usually build up an immunity to it, and re-infections are rare, or not as severe.

Marine angelfish and butterfly fish are the most common fish in the hobby to get this virus.  It normally shows up in newly imported fish, probably because of the stress they go through in the capture and shipping process.  The enlarge cells can be surgically removed, and when done usually do not come back.

Raccoon Butterfly with Lymphocystis.Removed Lymphocystis cells.

This Raccoon Butterfly (Chaetodon lunula) has a mass of Lymphocystis cells on its pectoral fin.  Photo to the right shows the cells that have been removed from the fin.

If the Lymphocystis is allowed to remain on the fish, there is a slight chance the fish could get a secondary bacterial infection.  Once the Lymphocystis infected cells are removed, normal fin regeneration will take place. 

Butterfly Fish after cells removed.

Photo of Raccoon Butterfly after removal of Lymphocystis cells.

Fish with this disease are hard for aquarium shops to sell.  If your up for a challenge, and you have a quarantine tank at home, when you find a fish with Lymphocystis in a store, you may be able to get the store to give you the fish for little or nothing.  Most aquarium shops would not want to keep a fish with Lymphocystis around as it can make potential customers leery about buying fish from their store.

While Lymphocystis is generally not fatal, it is unsightly.  The commercial value of fish with the disease is almost nothing.  With time the cells will eventually go away on their own, but this can take months in many cases.  Surgically removing the cells helps this process along and can restore the market value of the fish.

Published - 20070119

Aquaworld Sponsor