| Throughout history, fish have been true survivors. | | | | You will be able to notice some parasites by your |
| Carp have been dated back to around 20 million | | | | koi's behavior and appearance. |
| years ago, making them one of the oldest | | | | If you spot a fish constantly rubbing against rocks |
| species of fish around. In that time, they have | | | | or with unusual white spots on their body and/or |
| developed great immune systems, protecting | | | | fins, this is the sign of a parasite. To treat the |
| them from harsh changes in the climate, including | | | | water for parasites, you can buy a solution over |
| lack of food, and even most common bacteria | | | | the counter and also salt the water with a mild |
| and parasitic illnesses. | | | | solution. You should do this in a quarantine tank |
| However, the Japanese version of the carp, the | | | | where you should move this fish until they are |
| koi, is a different story entirely when it comes to | | | | cured. |
| immune systems. Due to the selective breeding | | | | Some of the bacterial infections your koi can pick |
| of colored "mutants", koi have compromised | | | | up include fin rot, cloudy eye, split fins, ulcers, and |
| immune systems and are extremely susceptible | | | | other body damage. This damage is easily seen |
| to illness. This is the price the fish have paid for | | | | on the fish. Just like parasitic infections, you should |
| being bred for beauty. | | | | remove the infected fish from the pond and put |
| There are two main categories of disease in koi: | | | | them into a quarantine tank. With the fish in |
| bacterial infection and parasitic infection. Both can | | | | quarantine, you can control the environment |
| be deadly to not only the infected fish, but also | | | | better and also isolate the bacteria from spreading |
| the entire colony. Any illness must be spotted and | | | | the disease to your other fish. |
| cared for immediately, lest you risk losing the | | | | However, with all diseases aside, the most |
| entire pond. | | | | dangerous factor to your fish here is the actual |
| Almost anything can bring on illness with a koi | | | | pond medication you use. This is why it's |
| pond. Although there's no real gauge to measure | | | | important to quarantine the individual fish before |
| the likelihood of illness occurring should you lapse in | | | | attempting to mediate the entire pond. |
| your pond upkeep, enough koi have succumb to | | | | Before purchasing any type of pond solution to rid |
| illness to form a pretty good baseline and to | | | | it of parasites and bacteria (bacteria being far less |
| advise owners that they should always be on the | | | | common with properly filtered waters), you |
| lookout for illness. Each time you go out to visit | | | | should find out exactly what it does and in what |
| your koi, you should check them for signs of | | | | amount you should use it in. Only medicate the |
| illness; moreover, make time to do so at least | | | | entire pond if all your fish are sick. If it's only one |
| once a week. | | | | or two, it's much easier to quarantine them and |
| Parasites include flukes on the skin and gills, costia, | | | | care for them in a controlled environment. |
| leeches, anchor worms, lice, and other parasites. | | | | |