Pond fish are susceptible to a number of viruses. These viruses have a broad but specific temperature tolerance, and this temperature range means that temperature variations can control them to a certain extent. Viral disease among fish tends to be limited by geography, and they are more dangerous to younger fish than adults. Testing and quarantine are the best ways to prevent viruses from infecting your fish, because once they do, drugs have limited effectiveness.

How will Viruses Affect Your Fish?

The effects that viruses have on fish will depend on the type. One of the oldest fish viruses is carp pox. Fish that have this virus will often display lesions which are raised, and they may also be milky in appearance. Carp pox itself is benign, but can be hazardous to fish if it results in a bacterial infection. Carp pox is also a problem among koi because these fish are sought after for their beauty, and this virus causes lesion which, while harmless, will make them unsightly in appearance.

Goldfish are susceptible to a condition called herpesviral hematopoietic necrosis. It is common among fish in the United States, and gold fish which are infected may become anorectic and display gills which are pale in appearance. The kidneys and spleen of the fish will often become enlarged, and gold fish which survive can become carriers. These carriers will display signs of the virus whenever they become stressed.

One virus which is particularly dangerous to koi and carp is koi herpesvirus. It is not common, but it is very dangerous and can impact native wildlife so any confirmed cases must be reported to U.S. Fish and Wildlife. The temperature of the water the fish reside in will determine the virus’s mortality rate. Maximum mortality will occur at water temperatures which range from 72 to 78 degrees Fahrenheit. At this temperature, the mortality rate of fish within the pond can range from 80 to 100 percent. Fish that survive koi herpesvirus can become carriers. Fish that have this disease will frequently swim near the surface, become red or white in appearance and develop hemorrhages.

Symptoms of Viruses

  • Lesions appear on the gills
  • Fish display ascites
  • Fish spleen or kidney becomes enlarged
  • Fish produce excessive skin mucus
  • The fish’s skin becomes dark
  • Hemorrhages appear on the fish

Fitz’s Fish Ponds is the Best Fish Care Specialist to Help You Combat Viruses

Fish viruses pose a great challenge, even to those who are experienced in pond fish care. Preventing the virus from appearing among the fish in your pond is much easier than getting rid of it once it does. This is why at Fitz’s Fish Ponds, we recommend certifications for replacement stocks as well as avoidance of carrier fish through quarantine. The majority of vaccines for fish today are geared towards bacterial disease, but we can implement vaccines which are designed for fish viruses as they become available on the market. Fitz’s Fish Ponds always makes use of the most cutting edge fish and pond treatment techniques, so contact us today to learn more about the pond services we provide!