Fish Disease Spotlight: Lymphocystis

Lymphocystis is a virus which afflicts fish, especially freshwater species. The good news is that unlike most viral diseases, which are untreatable and often fatal, Lymphocystis like Costia can be managed if the right steps are taken in time.

What Is Lymphocystis And Where Does It Come From?

There are lots of fish diseases out there, including numerous viruses, so it is first important to recognize the signs of Lymphocystis, so that it isn’t confused with another condition. Generally, fish which are infected will display nodules and clumps. They are usually pink or white in color and are shaped like cauliflowers. The clumps can be seen on the external surface of the fish’s skin, usually the fins. They range in size from small to medium, but can occasionally be larger.

Lymphocystis is a virus which resides in water and can function for a week with no host. The virus is transferred to fish through openings in their skin, usually from scratches or abrasions. The nodules will often be present in the spots where the virus first gained entry. However, some infected areas will be damaged but this can only be observed under a microscope.

Some wild fish have been discovered to have the virus latent in their system, which is one reason why you should never add wild fish to your pond without quarantining and testing them first. Lymphocystis has an incubation period which is long (as much as three months), and this makes it hard to detect and manage. Additionally, some of the fish which have the virus may not display nodules or clumps at all.

How To Treat Lymphocystis

The first thing you should do once you’ve confirmed your fish are infected with Lymphocystis is to take them out of the pond and isolate them. This will reduce their stress levels while insuring the disease isn’t transmitted to other healthy fish. You will next need to investigate the water itself, and improve both its quality and the greater pond environment by cleaning it, reviewing your filters and cleaning out any detritus you find.

Of equal importance is checking your fish’s diet. The fish should be given food which is rich in vitamins and fat, especially vitamin C. It is also recommended to use immune boosters as it will strengthen the immune system of your fish, making them resilient against illness. Lymphocystis almost always results from poor fish care and pond management. Many people are excited about the prospect of owning a pond or water garden, but are less enthusiastic about the maintenance that is required. They are too busy or lazy to do the necessary work themselves and don’t want to spend the money to hire a professional.

So they procrastinate, put off doing what needs to be done, and before they realize it the pond and fish are developing all sorts of problems. Once your fish have been isolated they should be given antibiotics. Although it won’t cure Lymphocystis it will block other pathogens from developing.