Some bacteria, especially Aeromonas and Pseudomonas, cause fin rot, skin disorders, and internal bleeding. These bacteria are common in freshwater and can cause diseases even at a temperature of 10 ° C, with the result that they can be a problem, especially in spring and autumn.

These bacteria often cause infections in fish that are weakened due to stress, injuries to the body, or poor water quality. When you try to keep the water quality in the pond optimal, you are also working on preventing the aforementioned problems.

Carp erythrodermatitis is a skin disease caused by a variant of Aeromonas, which leads to sores on the skin of infected koi. The disease will usually start with an injury, and the damage caused by the infection often leads to secondary fungal infections.

If nothing is done about this, this infection will be able to spread throughout the body resulting in internal bleeding and blood poisoning (septicemia). If a diagnosis is made in time, the infection can be controlled with a simple course of antibiotics. However, it should be borne in mind that problems can arise if these medicines have been used incorrectly before.

Hole blight is probably the term many koi enthusiasts use to describe the sores that appear on the koi’s body as a result of a bacterial infection.

Such holes undeniably lead to problems with osmosis (moisture balance of the koi). In a healthy koi (fish) there is a balance between the amount of water that enters the body (mainly via osmosis through the gills) and the water that leaves the body through the kidneys, as urine.

When a koi has holes in the body, the water penetrates unimpeded through the damaged skin and puts an extra strain on the kidneys, causing them to fall out. In these circumstances, it may well be worth adding salt to the water, as much as 3 grams per liter of water.

This solution of 0, 3 percent helps to restore the osmosis balance to the wound and to relieve the workload on the kidneys. With a salt treatment, the balance can often be restored in stressed koi. As mentioned, stressed koi are more prone to bacterial infections.

Salt is a powerful disinfectant that often eliminates pathogenic bacteria before they cause problems.

Treatment: see Products: Medicines; Cytofex, FMC-50, FMGMix, Acriflavin, Formalin, Formaldehyde, Malachit, Malachite Green.