As a responsible Koi pond owner, you will want to ensure that you protect your fish from Koi bacterial and fungal diseases. The best way to do this is to do a daily visual check on each fish. Feeding time offers the best opportunities to notice if anything seems “off” in your Koi’s appearance and/or behavior.
First, I will review how to recognize and treat some common bacterial forms of Koi disease.
Symptoms of bacterial hemorrhagic septicemia include red streaking on the fins and body or redness on the body itself. Your fish may also have open sores and/or loss of scales. For treatment, you should use an antibiotic Koi disease medication or oxytetracycline in the feed or a fungicide/protozoacid dip/dip treatment in the water.
Red, open sores or ulcerations and damage to the fins and/or tail (sometimes they can be eaten entirely) are indicative of Pseudomonas bacteria. Again, use a Koi disease antibiotic medication or neomycin or kanamycin in their feed and a protozoacid fungicide/dip/dip in the water.
FlexiBacteria, which causes Columnaris disease, is indicated when a white, thin, furry coating appears on the body and fins. It looks like a fungus. For treatment use sodium sulfathiazole.
Piscine Tuberculosis is a bacteria that must be treated very carefully, as it can spread to humans. Some signs of Piscine tuberculosis are; your fish has been sick for several months, is lethargic, anorexic, shows scales or loss of fins, and has a distended stomach. You should treat this Koi disease with Kanamycin and Vitamin B6 for at least 30 days.
Furunculosis is another bacterial disease to watch out for. One or more fish will have skin blisters that are filled with a clear or yellowish fluid. These blisters will burst and become large open sores. These fish should be treated with furzolidone powder for 10 to 14 days.
We are now going to take a look at some of the more common fungal disorders that are considered a Koi disease.
If your fish get the water mold infection, it will look like they have green algae growing on them. Effective forms of treatment are the use of erythromycin for 10 days or a fungicide/protozoacid dip/bath treatment in water.
Symptoms displayed by fish with the Saprolegnia fungus are white, cottony swellings on the skin and gills that will turn into red, open sores within 24 hours. For this Koi disease, you will want to treat it with copper sulfate.
When fish get brachymycosis, they appear weak and lethargic and gasp from lack of air. Some fish are left behind from the school in the pond. This is a very serious Koi disease and a large number of deaths can occur in your pond. Be sure to treat all fish with a fungicide/protozoacid dip/dip treatment in the water. It’s also important to make sure you don’t overcrowd the fish and keep the water quality high.
With all of these fungal disorders, it is very important to keep your pond water filtered, free from overcrowding, and free of excess organic material. In fact, these measures are not only important for these fungal disorders, but for any Koi disease.