Parasite Treatments
In my previous article on koi parasites, I included a list of recommended treatments for each parasite concerned. Since then, a number of people have asked for specific recommendations as to the best treatments to use from this list to eradicate particular parasites
Like many koi related questions, there is no definitive ‘right’ answer to the issues posed here either! Recommended treatments for parasites can vary according to pond conditions and environmental issues, for example.
Let’s try and explain.
Some chemicals won’t work at low temperatures and some don’t work so well at high temperatures either! Potassium Permanganate is the only effective treatment to use in cold water and works well at any temperatures. However at temperatures over around 18 deg C (and upwards) extra aeration must be used with Potassium of you may find you suffocate your fish since this chemical strips large amounts of Oxygen from the water.
In addition as the pond water temperature changes, so does the life cycle of the parasite. As you know, generally most treatments have to be repeated in order to kill all stages of the parasite concerned. This is because most chemicals cannot kill parasite eggs and you must wait until the eggs hatch before retreating and killing the live parasites. If you leave your repeat dose too long the parasites will have hatched and the hatchlings will have laid eggs again! Too little time between treatments and eggs will be present and the treatment will only be partially effective. So how long do you wait? Well life cycles are influenced by water temperature. At cold water temperatures some parasites take a month to complete their life cycle and some may not complete at all. At high temperatures a complete life cycle can be completed in 3-4 days. Tricky isn’t it?
Discussing this very subject with a member recently, we concluded that one of the biggest problems is that there is not enough information to the average hobbyist about parasite life cycles – most of the information you read in the books is too generalised. However there are now a number of good books available specifically on fish diseases, and whilst these are not specifically aimed at koi, most cover the subject of parasites in much more detail.
Sudden changes in temperature can also trigger an outbreak of parasites. For example, whitespot, which is endemic in many fresh water species, is a cold water parasite commonly triggered into action by moving fish from warm to cold water or simply by rapid changes in a koi's environment.
Some chemicals work differently as the pH varies. For example Chloramine T is not nearly as effective at high pH (which most of the Chiltern Section will have) as at low pH. The recommended dose rates for Chloramine T are between 1.5 and 2 gms per ton – but this is the dose rate for low pH. At pH 8.0 and above, the recommended dose rate goes up to 5mg per ton! Guess what happens to your filters if you use it at that rate? This is one of the reasons that whilst Chloramine T is a very good disinfectant, it is not always effective at eradicating targeted parasites.
You simply can’t use certain chemicals in your pond if you have goldfish, Orfe, Tench or Rudd. As the chemicals will poleaxe the fish as well as the parasites!. Ones to watch are the Organophosphates, Masoten, Dimlin and Supaverm.
If you do have other species present, you may therefore have to revert to a less effective (but safer) remedy with which to treat the pond – or move your other fish to a temporary home whilst treating your koi.
Sounds obvious I know. If you koi have parasites they are not going to be in prime condition are they! What I mean by this is that often older inhabitants of koi ponds won’t take so kindly to chemicals as some of the more sprightly inhabitants. Often, old koi will have sustained some gill damage throughout their lives as a result of periods of living in an artificial environment where water quality was not always as good as it should have been. When subjected to some of the more aggressive chemicals, older koi can succumb whilst the younger koi are fine.
If you have some older koi that might be at risk then you may want to resort to a less aggressive chemical. Supaverm and Masoten are the most likely to cause concern.
A complex issue to get into but why have your koi become infested with parasites in the first place? It (they) could have been introduced into the pond with parasites. They could have inherited them from an existing pond inhabitant. Poor water quality may have stressed the koi which will then have attracted parasites, the fish could be suffering with some other form of illness which debilitates it causing parasite attack.
Parasites are opportunistic. Healthy koi are normally able to keep parasite numbers under control. Most koi carry some parasites just like dogs and cats carry fleas. Healthy mucus on a koi damages parasite mobility and koi will produce more mucus (sometimes to excess) when parasites are present in numbers.
If your koi has attracted parasites because it has become ill or stressed, it is very common to find more than one type of parasite present on a scrape. The choice of treatment is therefore more difficult, as you may have to use one chemical for one parasite and another for a different one. Which do you use first? Try and kill the most dangerous parasite first. The most dangerous one is normally the one present in higher numbers and to establish this, you may have to take more than one scrape from the same fish and take a scrape from a second fish to see what you find. Never, under any circumstances mix different chemicals together unless recommended by the manufacturer. You may kill more than the parasites.
If you have koi with parasites, you will most commonly need to treat with Potassium Permanganate, ChloramineT, Malachite and Formalin or Acraflavine . All of these chemicals will affect your filters, but to different degrees. If you have a mature filter this will be of less concern, but if you have an immature set up – less than 6 months old, you may wish to take more care in your choice of treatment so that you do as little damage to your filter as possible.
Probably Chloramine T will damage filters more than any other chemical, then Potassium, but again effects will vary according to specific circumstances.
Ironically, the more aggressive Organophosphates do not, as far as I am aware, damage filters, and therefore may be your first choice of treatment where your filters are immature.
The more you read, the more confused you can become! Different publications may print differing dose rates for the same chemical which only serves to confuse more. However, different manufacturers package the same chemicals with differing strengths so you will always need to follow the instructions on the bottle and NEVER from a book or article as this may refer to a different strength of the chemical. Acraflavine, Malachite and Formalin are sold commercially in different strengths so use caution when using.
Confused now? Me too!
Summing up, all parasite treatments are chemicals which we would not wish to add to our pond water at all unless absolutely necessary. Most have side affects and all should be used with caution.
Normally the correct dose of the correct chemical repeated at the correct frequency will eradicate the parasite. So why sometimes do we report that our treatment has not been totally effective?
Normally the reasons are fairly straightforward:
To add to the confusion as potassium and Chloramine T are oxidising agents, they would at the correct strength kill ALL parasites. Unfortunately at the required strength, they would also kill the fish!
The other very important thing to remember when choosing your medication is how long each treatment remains effective in the pond relevant to the life cycle of the particular parasite in question.
The chemical must obviously remain active in the water long enough to kill all juvenile and adult parasites and the time required varies.
Chloramine T is only effective in the water for around 12 hours and the dose is therefore normally repeated daily or every other day to ensure adequate kill rates. It should also be used in the evening rather than in the morning as UV light breaks down this chemical very quickly indeed.
Potassium is effective for at least 24 hours in the water whilst Malachite and Formalin are normally effective for 3 or 4 days. Remember however that these time vary considerable with temperature and the amount of UV light hitting the water.
In conclusion, before treating your pond with any chemical for suspected parasite infestation, you should take steps to identify the culprit(s) and then choose the most appropriate remedy depending on the factors discussed above. Diving in too rapidly and treating with the wrong chemical at the wrong time/dose/frequency can do more damage than not treating at all.
There is now no excuse for not being in a position to identify your unwanted guests as the club owns microscopes which are available for hire and help is always at hand should you need advice or assistance with treatments.
In conclusion, my preferred parasite medications are:-
1. Whitespot - Acraflavine with salt at 1/2 ounce per gallon. Two treatments required. 2nd favaourite, Malachite plus salt at 1/2 oz per gallon. no Formalin. Use above 54 Deg F (12 Deg C.)
2. Costia - Potassium Permanganate plus salt at 1/2 oz per gallon. Any Temperature
3. Trichodena - Potassium Permanagante plus salt at 1/2 oz per gallon. Any Temperature
4. Chilodonella - Potassium Permanganate plus salt at 1/2 oz per gallon. Any Temperature
5 Flukes (Body and Gill) - Supaverm at 5ml per 1000 gallons only. Repeat if required. 2nd choice - Potassium Permanaganate at 2gm per 220 gallons with salt at 3/4 oz per gallon. Max temp 20 deg C.
6. Argulus (Fish louse), Lernea (Anchor Worm) and Leeches - Supaverm at 10ml per 1000 gallons. Use only once. 2nd choice Paradex - use as directed. Use above 54 Deg F ( 12 Deg C.)
Happy koi keeping!