This is always a problem discussing because there are hardly any treatments which are made for Koi.
It’s also a subject where everyone has different opinions on how to do things.
I want to cover the very basic methods of treating Koi, things you can do by yourself without having to call a professional out. I do not direct the term professional at Vets. They just don’t cover anything to do with Koi or fish for that matter. They can get the treatments but they really have no idea of how to use them. Most professional Koi dealers have a good knowledge of how to treat Koi because they are doing it all the time on their own fish. There are also treatment officers in Koi clubs all over the world so finding help shouldn’t be far away.
In my opinion 90% of problems with Koi are down to parasites. Caught early all parasites can be eradicated with ease and little discomfort to the fish. Microscopes can be the most important tool to a Koi Keeper; unfortunately they can also be the worst. I myself use them every day because I need to make sure Koi for Sale are sold parasite free. Many people are relaxed and experienced enough to take a mucus scrape if they notice anything different with their own fish. Koi care is different with each person, many Koi Keepers can tell straight away if they have a problem just with the reaction of their Koi, thats when they take a scrape. New Koi Keepers who have just bought a microscope can be very paranoid; they end up taking 5 scrapes and possibly doing damage to the Koi only to panic about seeing a few bubbles. My advice would be to buy a microscope and ask someone to come to who know exactly what they are doing and go through the basics.
There are ways to spot parasites or symptoms of parasites so you can look for the danger signs. These are not guarantees, more like guidelines or dangers to look out for. The most common thing to look for is ‘flicking’ or ‘flashing’ this is when a Koi will swim and turn on the bottom or sides of the pond, they really are scratching an itch. However water quality can also cause a Koi to do the same thing but I’d say that it’s probably parasites. Excess mucus appearing on and around the head can also be a sign there could be parasites in the pond. Koi produce excess mucus to combat problems. It’s like a natural defence they have, so when you see Koi producing excess mucus it’s a sure sign you must check them. Koi grouping at the bottom of the pond is another sign there could be parasites as is Koi acting lethargic at the surface of the pond. There are other reasons your Koi could show these symptoms but with a microscope you can easily find the problem.
With experience and knowledge of your own Koi will come the ability to spot when your fish are not happy. You feed them each and every day; you know how your own Koi act so any change from the ‘norm’ you will see and act upon.
Unfortunately there is not one magic medicine that will eradicate all parasites, I wish there was. We can group parasites into different treatment brackets though, which helps.
Let’s look at the most common parasites that effect Koi today
Click to enlarge
Treatments to eradicate the above parasites come in all shapes and sizes but most do exactly what they say they will do.
Potassium Permanganate will kill Costia and Trichodina. A pond dose of 1.5 grams to 220gallons is normally sufficient to kill the parasites. Costia is a horrible parasite and in most cases will need a follow up dose 5 days apart. Trichodina isn’t as bad as Costia but there are no safe parasites. Ignore people who say “It won’t do any harm in small quantities” Just because it won’t physically hurt the Koi, the Koi will still itch! When a Koi does itch there is a good chance it can injure itself, which in turn can cause bacterial infections. Eradicating parasites fully can lower the chances of any further problems which parasites will cause.
Malachite Green and Formalin is an age old treatment. The problem we have with it now is that it dosent do the same job as it has always done. Its great for white spot, will kill it dead over night. Its also excellent for Chilodonella. It used to be great for flukes, however in recent years it does not seem to have an effect on them and other treatments are needed.
At the time of writing the best things to eradicate Skin/Gill flukes is a product called Flubanol. Re packaged by some places and sold as ‘Fluke M’. This is a very good way of getting rid of flukes, fast and efficient. There is also ‘Supaverm’ which is my personal choice of fluke treatment but some people don’t like using it and prefer Fluke M.
Argalus/Fish lice is a terrible parasite when it gets hold. Its quite rare these days in most Koi ponds but will get into many wildlife ponds. The main treatments in the UK are banned because they are Organophosphates which are now illegal. The best bet in the UK is to try and get hold of some snail treatment, Argalus have shells so the same treatment should work.
Anchor worm (Lernea) You shouldn’t really suffer much with Anchor worm. Its most commonly found on newly imported Koi. The best treatment is Dimilin. This will not kill the Anchor work but it will make them sterile. The worms will still need picking off the Koi.
That pretty much covers how to simply eradicate the parasites. The worst possible thing you can do is guess which parasite it is. Thats why you must either invest in a microscope or call out your local Koi Dealer who will have the microscope and the treatments needed to get rid of any nasty parasites.
Another important thing to remember is that none of the products I have listed for killing parasites are made for the Koi industry, none! Malachite green is a dye. Flubanol is a dog wormer…Supaverm is a sheep wormer…There are no remedies made specifically for our fish. These products have been tried and tested over the years just to get the correct dosage rates. It’s the same with antibiotics that people use, not one single one is made for Koi, the most common one being Baytril which is used for Cats and dogs.
The most important thing when we come to treating our ponds is this; YOU MUST KNOW THE EXACT GALLONAGE of your pond. There is no point guessing or trying to work out a pond which has a shelf in it and is deeper at one end than the other, this is crazy! Treatments used in the Koi industry have to be exact. Over dosing can cause major problems while under dosing will do nothing. No matter how much of a big job it would be to empty your system and refill it, its 100% worth doing. A simple flow metre can be bought/borrowed which will give you your exact volume to the gallon! No more guessing.
As I have said, Parasites can lead to the most common problems with our Koi, from ulcers to full bacterial infections. Killing the parasite is a must.
Mucus scrapes are pretty easy to do. Once you have done a few it will become like second nature. Its the same when spotting parasites, once your eye is ‘trained’ to the parasite then you will see them each time. Different people scrape in different places; I always take scrapes behind the gill plate and down the body. Some parasites will live around the gill areas such as Gill Flukes and Costia. A parasite like Costia can also only be in one place on the fish. I have seen this many times when scrapes have been taken on the body and found nothing at all but then when I have taken a scrape from somewhere else on the Koi, Costia has been all over the place.
Microscope attched to Laptop
Remember though, unless you think there is a problem on the Koi and are seeing symptoms which lead you to believe there are parasites, don’t take loads of scrapes from the same fish. If you are taking a scrape as a scheduled general scrape then just do a couple of scrapes on a couple of fish. I would recommend once every 2 weeks.
There are many arguments about how many parasites need to be seen before you add a treatment, while I agree that the treatments we use on our fish are very harsh and they do not like it one little bit, I also think that one parasite will make a fish ‘flash’ which in turn can be very harmful.
Random treating is never a good idea; only treat when you need to treat. If you think there is a problem in your pond then get someone to come and check them out.
Parasites are not the only problem when it comes to looking after our Koi.
One of the biggest problems to Koi Keepers in the dreaded bacterial infections! This can lead to terrible and lasting problems with our Koi.
All it takes is a single scale to be knocked off, a single ‘spook’ where the Koi suddenly dart away and knock a pipe or a pump or anything which could be in the pond. In then takes the smallest amount of bacteria to infect the small scratch and turn it into a big wound.
There are products on the market which help to combat bacteria and can be used as a general monthly treatment, they are inexpensive and effective! They can save you many problems.
If you treat as a preventative when it comes to bacterial infections then even if the Koi does suffer a tiny ‘knock’ in the pond, because you already treat the pond with an anti bacterial treatment then the pond will heal the Koi and in some cases you will never have even noticed. Keeping clean water is very important. It is important to remember when it comes to Anti Bacterial treatments that at large doses (not general treatment doses) they will knock your filter back. Unfortunately there isn’t a way to selectively kill good or bad bacteria. Treatments will affect both kinds. A strong mature filter will regenerate in a small amount of time. This will only happen when you are dealing with a major bacterial infection anyway. Preventative treatments will not have any affect.
Tim Waddington - 2009