Well I have discovered that koi are fiendishly difficult to keep. Or compared to what I thought ("Ah, it's just a carp... they live in the Liesbeeck river...").
One of the symptoms of problems with Koi is ulcer disease - it's very common, and should you keep koi, you will need to deal with it at one time or another.
So what does it look like? A picture of a typical ulcer on a koi is presented below.
|A picture of a typical ulcer occurring in koi. Picture: USA Koi|
|Close up of a koi ulcer. Picture: USA Koi|
Ulcers are distressing and seldom do they simply go away by themselves. In fact, unchecked, they will literally eat away at your koi until the fish can no longer survive.
Treating ulcers is difficult. Ulcers start as symptoms of other issues. Common to all of these issues is stress. Stress lowers the fish's natural immunity and results in a bacterial infection. Treating the ulcer requires treating the wound, the bacterial infection and the underlying cause of the stress.
The most common cause of stress is poor water quality. This must be ruled out before considering anything else.
Next on the list of ulcer causes are parasites. This is what affected me. I bought two fish late last year that introduced parasites into the pond. A sure fire way of knowing whether this is the cause of your problems is to watch out for flashing. Fish with parasites will quickly dart up against something and rub to relieve itching. Costia and flukes are common parasites that cause this behaviour. The parasite will cause a raw spot under the fishes scales, providing an opportunity for bacteria to infect the wound.
Ulcer disease can also appear as mouth and fin rot. This alarming form of the disease rapidly cause gaping holes around the mouth of a fish or on its fins. Ultimately this is what I ended up with.
I have tried everything in the book to treat my fish. I am finally showing some signs of success - after losing three fish.
To treat the fish, three steps were required:
- Treat the underlying cause - water quality issues may involve a complete reworking of a filtration system, so be prepared for the difficult issues here
- Treat the ulcer topically - typically this is through removal of necrotic (dead) tissue, application of a disinfectant such as mecurochrome - although I highly recommend going to the most effective / dangerous means - potassium permanganate applied directly to the wound. Blow dry (with a hair dryer on neutral temperature or with your mouth), and then apply a sealant. Friar's Balsalm is typically used, but I have found wound gel works far more effectively.
- Treat bacteria and parasites in the water - this is difficult, as it depends on the parasite and bacteria you are dealing with. Common to almost all is dosing the water with salt and holding a concentration of 0,3 to 0,6%. Many koi keepers will maintain a salt concentration of 0,3% indefinitely. For mouth and fin rot, I found that a potassium permanganate "bomb" to kill parasites and bacteria quickly followed by acraflavine (two doses, one immediately after the potassium permanganate and one four days later) works best.
- Depending on the severity of the ulcer, inject the fish with antibiotics. This is nerve wracking, but critical to reverse a really bad ulcer.
I've included a picture of injecting a koi below. It was the hardest thing that I had to do. You can get a vet to pay three visits to perform the task, but this is prohibitively expensive. As a koi keeper, it is a fairly important skill to learn. You will have to obtain an antibiotic and injection syringe from a vet.
Finally, I believe that koi feel pain. Many dispute this, citing their being cold blooded, etc. However, before I began using an anesthetic, when applying treatment to the koi, they were highly upset and even made a squeaking sound (I kid you not - I have a witness). So when handling your koi for treatment, I highly recommend using an anesthetic dip prior to the event. Besides less stress for the fish, it helps reduce stress in the handler!
|How to inject a koi. Picture: USA Koi|
Update: I have updated this picture with an alternative injection spot (than the previously shown one between the vent and pelvic fins). I find this one much easier.