Carp Pox Treatment for Koi

Carp pox on a koi

Carp pox, sometimes known as koi pox, is a herpes viral illness that affects ornamental koi. Koi with enlarged epithelial growths along the dorsal ridge, flanks, and fins have this condition. It's a pretty harmless sickness that simply affects the fish's appearance and has no effect on their general health or longevity. Secondary skin infections can occur in severe outbreaks, but they are uncommon.

What is Carp Pox?

Cyprinid herpesvirus-1, a prevalent virus in ornamental koi, manifests itself as carp pox. The dorsal ridge, sides, fins, and mouth of your koi will develop abnormal skin growths as a result of this infection. Depending on your fish's unique stress level and immunological capabilities, they might be moderate or severe.

Symptoms of Carp Pox

  • "Candle wax" lesions
  • "Frosting" on skin
  • Thickening of fins, especially the cranial edge
  • Growths around/in mouth

Carp pox clinical indicators, like many other fish illnesses, are temperature dependant. The Carp Pox herpes virus causes skin lesions that are more frequent at chilly water temperatures. A koi's immune system becomes substantially more active and their skin turnover accelerates as the water temperature rises to the high 60s to 70s Fahrenheit. This will help to reduce or perhaps eliminate the carp pox lesions. This does not indicate the virus is no longer present; it just means the infection's clinical symptoms are no longer present. When the water cools down for the season, the signals will most likely return.

Many internet forums advise removing the troublesome plaques surgically, however this is not advised. Not only are you putting your fish through painful surgery that might lead to secondary bacterial illnesses, but the lesions will also reoccur. Even though the skin sores come and go, once the virus has infected your fish and caused clinical indications, they will be sick for life. Again, this is not a life-threatening ailment, and your fish's outward appearance will merely alter.

Causes of Carp Pox

The herpes virus Cyprinid herpesvirus-1 causes carp pox. Cyprinid herpesvirus-3 (Koi Herpes Virus) and Cyprinid herpesvirus-2 (Goldfish Hematopoietic Necrosis Virus) are cousins. The virus, like other herpes viruses, has a latent or carrier condition that allows it to survive within an individual without causing any visible symptoms. Fish can become contaminated at an early age and not exhibit clinical indications for years. Secondary stress can induce skin sores and infect other fish through direct touch or waterborne transfer.

Once a fish in your pond has been diagnosed with carp pox, all other fish in the pond are presumed to be potential carriers. Unless numerous possible stressors, such as poor water quality, are present, it is unusual for more than one or two fish to display clinical indications at the same time in an infected pond.

Carassius auratus, a kind of goldfish, has been shown to contain the Koi Herpes Virus, suggesting that they may possibly carry carp pox. When goldfish are carriers, they do not display symptoms of KHV, therefore it's likely that they can spread carp pox between infected systems without presenting clinical indications.


Latent virions, like all other herpes viruses, burrow deep into brain tissue, making them hard to remove or cure. Herpes is a life sentence for any animal. There is currently no therapy available. Plaques should not be surgically removed since they will merely grow back.

Raising the temperature of your water might help to ease the symptoms of carp pox. This will help your koi fight the sickness more effectively and may perhaps eliminate symptoms totally. This does not indicate the virus has left your fish; lesions will reappear as the water cools.

How to Prevent Carp Pox

Proper quarantine practices are required for all infectious fish diseases to safeguard the health and safety of all your fish. Pond fish are no different, although they'll need a bigger holding tank. Do not believe koi vendors when they say their fish have been quarantined correctly. Inquire about their practices in detail, including length, treatments, mixing of fish from various suppliers, testing, and whether they've had an aquatic veterinarian consult. Shop elsewhere if they are afraid to share any of this information.

Carp pox testing is accessible through your aquatic veterinarian for fish who are actively presenting symptoms. At this moment, there is no carrier status test available. Carp pox should not be excessively bothered by koi owners because it is a non-lethal illness with modest symptoms. According to aquatic vets, this is a highly prevalent illness, and having a pond that is not infested with carp pox is uncommon in certain locations.

Is Carp Pox Contagious to Other Fish?

Other cyprinid herpes viruses have been shown to be transmitted by other fish, such as goldfish, however those animals do not display any clinical indications. Because carp pox is not a fatal illness, no research has been done to see if additional species have verified carrier status.