I apologize that no one has responded to your question sooner. Different experts come online at various times. I just came online and saw your question. My name is ***** ***** I’m a biologist with a special interest in fish. I'm sorry to hear of this problem.
I'm so very sorry to give you bad news.Whirling disease is caused by Myxobolus cerebralis, a parasite. These parasites infest the tissues around the inner ear and the brain, interfering with balance mechanisms. Some fish that get it will twirl in circles. Some will float head down. Others may develop a bent spine. Emaciation commonly occurs in most fish that are affected as the infection progresses. Whirling disease has become fairly common in koi, goldfish, and tropical fish. It is thought to be carried in tubifex worms and possibly other similar foods, whether live or freeze-dried, but of course in a pond, it could have been brought in through many different organisms. It is most often fatal.
You'll need to make a decision. Most people euthanize fish when they begin to exhibit whirling. If that's what you prefer to do, let me know and I'll give you the most humane method (there's no additional fee). I only give it on request because some people don't even like to read about it.
If you don't want to euthanize, there are still two choices. The affected fish do need to be removed from the pond. If they die in your pond, millions of the little parasites will be released from their bodies almost immediately upon death. That greatly increases the chances of more fish being infested. You could put them in a big RubberMaid tote or a child's plastic wading pool with a filter running, and simply wait for them to pass away. Rarely, a fish will seem to recover, but that fish will always carry the parasites.
The other option is to try to treat the fish. It is only rarely successful, but there have been cases of a cure. Treatment has to be carried out for an extended time, usually about 3 months. Not all fish respond to it. Only one drug has been found to ever work: kanamycin. You can either place the fish in a hospital tank (a large RubberMaid tote works). You can also treat the entire pond, but that does get expensive. While here in the States we can buy this drug in pet stores and online, in the UK it is only available by prescription from a vet.
Itt can be combined with Furan 2 and Metronidazole for stubborn bacterial infections. Whirling disease is stubborn, so you may want to consider this. These drugs may also require prescriptions. This link will take you to a directory of UK fish vets:
If you have more questions, just let me know. I am so sorry you are dealing with this nasty parasite.
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