Fish Health

Worthing & District Section BKKS

FISH HEALTH

1. K,H.V. Warning

2. Basic Do's and Don'ts for Koi Fish Keeping

3. Parasites & Treatment

4. Spring_Care - Suggested Husbandry

Winter Care and Aeromonas Alley

Posted by James P ( James P Reilly) on 23rd November 2007 on Nishikikoi International Magazine Message Board

As discussed, Aeromonas Alley is a theory advanced by an old friend ( Luther C.Chien) and fellow ZNA club member in the 1990s as a way of explaining why so many cases of aeromonas were seen in the spring of each year. This very plausible theory suggested that fish & bacteria came together in a ‘perfect storm’ due to temperatures. And this zone of temperature was named ‘Aeromonas Alley’. At the heart of this theory were two basic snippets of information:

1) that aeromonas was most active in high reproduction numbers in the 50- 60 F degree range and
2) that koi’s immune system performance decreased as water got colder and actually became dormant at the 50 F mark. This is perhaps the greatest flaw in building any case for the theory of AA.

Further it was suggested that the way to avoid this collision course was to skip or jump over this range or at least prepare for infection in the ‘alley’ of temperatures.

This is a very good primer for beginners , especially those that keep their koi under ice or out all winter in 35- 45 F water.

But for the advanced keepers among us or maybe for all koi keepers in the year 2008 , we should understand that this is not an accurate theory based on greater observation of koi as a four season animal.

I will submit the evidence and I think the facts will make the point.

1) Aeromonas is a very common potential disease that is seen mostly in LATE spring. The precursor to actual infection indeed requires a weakened host and the presence of the pathogen. And this is why AA theory is beneficial to understand as a primer for beginners.
In a variation, the vector can be a parasite that physically carries aeromonas or provides a sight of damage on a weakened fish, so that aeromonas can be become the opportunistic pathogen it was designed to be. This is all compatible with the aeromonas theory so far.

2) the dynamic however quickly becomes more complicated and soon leads the observer away from that AA theory as we add in evidence. Aeromonas is indeed very common in the high 60 F-low 70 F range. And common all summer in organically rich ponds that house fish weakened by water quality issues. And often, even more common than fish living at 45- 55 F.
In fact, koi are temperate water fish. They are not tropical fish. And much of our early view of koi is based on the early studies from the tropical fish medical and aquarium books. This still lingers with us and many hobbyists use the temperature range of 82- 84 F to warm up koi’s immune response based on tropical fish recommendations. Koi are MOST metabolically EFFICIENT between 65- 74 F. And efficiency begins to fall off modestly, then greatly, as you move away from this range. In addition we used to believe that 50 F was the absolute cut off for koi digestion and that food would block and decay in the gut at this temperature. A little research will show that koi digest down to 46 F and that their core temperature can be as much as 2 degrees higher than surrounding water, making digestion possible down to 44 F, there are good reasons NOT to feed all the way down to 44F. I mention this because it will give the reader a different view of koi and also because Aeromonas Alley was created against this backdrop of seeing koi as creatures that ‘shut down’ at 50 F and were somehow helpless and vulnerable.

3) Many of us have kept our adapted hardy adult koi in 45 -55 and 55- 60 F ranges all winter and have not seen an aeromonas infection for many many years. This had us all suspecting that there was more to aeromonas alley than temperature collision. And as we all did culture and count tests for aeromonas in our individual ponds we learned several things:
a) aeromonas does not do well in properly designed ponds
b) yet, aeromonas is always present in some amount in all koi ponds as a natural species, as is pseudomonas.
c) aeromonas is at it’s largest count in AUTUMN and spring is the SECOND highest natural count. Yet, aeromonas infections are comparatively rare in Autumn ponds when the koi and water quality are both at their best.

4) The koi has always been seen as a ‘four season fish’ by the observant Japanese breeder community. Koi have only been bred by the Niigata region farmers for 150 years or so. And modern breeding efforts were only commercialized for export since the end of WWII. But Japanese farmers have been breeding carp for hundreds of years. Yet it was not until very recently that western collectors of fancy carp have been able to identify and match the science of a four season fish with the observations of Japanese farmers. And the results dove-tail perfectly! Koi go through four distinct metabolic cycles prompted by temperature, light and changing diet. Everything changes, including the growth patterns, reproductive cell development and direction of energy derived from food.
The wild carp has been honed by nature under the edict of ‘survival of the fittest’. And winter is a time where only the strong survive. Yet actual death, will tend to come much later. Typically, in the next season.
Our koi are weaker versions of their cousin carp and they have similar, albeit narrower, ranges of survival. And so, in every school or population of koi we have individuals that will be stressed more by environmental conditions than others within a band of optimal range vs survival range. One form of stress that effects our koi is cold water. This stress can be defined in terms of absolute temperatures ( say , 34 F for young fish) or in terms of length of exposure ( 16 weeks at 42 F for example). It is during this time that a well documented phenomena known as G.A.S. ( General Adaptive Syndrome) takes over koi that have experienced too long a winter or too severe a winter.
This GAS event, characterized by three separate and measurable stages, is a stress response created within the fish in order to survive a life threatening encounter- and winter is one of these stressors. At first the body surges with hormones to meet the stressor danger. This is meant to be a temporary fix. But if the stressor can’t be escaped from, the second stage involves shutting down all ‘services’ that are deemed ‘non- essential’ for the time being and metabolically concentrating or coping with this stressor through adaptation. Stage three is a physiological acknowledgment that ‘escape is not possible’ and ‘ adaptation is not working’ so endurance is all that is left until one of two things happens- the stressor modulates and the fish gathers strength - OR- the fish eventually succumbs. The cause of death itself can be from secondary invaders or from system failure as the released hormones reek havoc with circulation, cardiac and blood pressure and immune response. In this stage, a fish can be doomed as the recovery is impossible. In this case, aeromonas is simply being the opportunistic pathogen it is defined as. If you add in organically rich water to the long freezing winter, you have created a large aeromonas population.

I have said before that as a theory AA and what really happens could be looked at as so much semantics. But in truth, a deeper understanding of the try dynamic will arm a keeper to approach and respond better to health issues that might arise in Spring. Or ideally, have a keeper avoid problems all together. Every year, my koi and the koi of hundreds of other keepers I know, experience a rise in temperature thru the 50s and 60s and yet, our bottles of antibiotics sit on shelves unopened, long after expiration date. The key is preparation of koi for winter, monitoring the depth and breathe of winter water temperatures and seeing to the quality of winter water. Aeromonas lives along side our koi at all times. The idea is to keep the species as so much background noise and maintain strong healthy fish. The two will never meet in ‘any alley’ of any kind if these things are tended to.

JR

Chloramines Explained...Posted 10 March 2007

Chlorine treatment of tap water has been long established but the increasing of Chloramines in recent times may be still new enough to remain something of a mystery to many fish keepers. The following information has been extracted from a leaflet sent to consumers of the Severn Trent Water Company: although originating in the Nottingham area, the facts detailed are probably just as relevant to fish keepers in most other areas.

Chloramine is a combination of Chlorine and Ammonia and many people feel that treating water with this, rather than Chlorine alone, gives an improvement in taste. Chloramines are both safe and well-established as part of water disinfectant treatment, they have been in use in the UK, the United States of America and Canada for decades. Chlorinated water is safe for drinking, bathing, cooking and all uses we have for water everyday.

However, there are drawbacks with its use, and people requiring kidney dialysis, as well as fish keepers, need to take special care. Kidney dialysis patients must remove chloramines from the water fed into their machines in the dialysis process if water comes into contact with blood across a permeable membrane, Chloramine, like Chlorine, is toxic in this context and must be removed.

(Drinking treated water however, is safe because the digestive process neutralises the chloramines before it reaches the bloodstream, even dialysis patients can drink, cook and bathe in treated water without worry as only direct chloramines contact with the blood is dangerous).

Removal can be done by adding ascorbic acid or using granular activated carbon (GAC) treatment: this is the responsibility of the medical centres operating the dialysis treatments. Patients with home dialysis machines should check with their local renal unit who will recommend the appropriate type of water treatment.

Fish keepers also need to remove Chloramines from water used for aquariums and ponds, either directly as in freshwater tanks/ponds and for water used with salts to make up synthetic seawater for marine aquariums. Although chlorine is also toxic to fish, it gasses off rapidly, especially when fast water flow rates are employed: the turbulence blows off the chlorine and vigorous aeration will do the same. Leaving water to stand for a few days also dispels chlorine but chloramines treated water will not respond to any of these treatments – chloramines may take weeks to disappear.

De-chlorinating agents available from your aquatic stockist will work very well for chloramines as they do for chlorine: alternatively a GAC filter used at a sow flow rate (to allow sufficient contact time) is the next best thing. Always follow the instructions given with de-chlorinators and carbon filters as close as possible.

Chloramines affect the fish directly because it can come into direct contact with the bloodstream through the gill membrane. A peculiar anomaly is that while chloramines (an ammonia based combination) is toxic to fish, they are apparently not affected by the ammonia they excrete naturally themselves from the same gill during respiration.

Ammonia can be produced too when chloramines are chemically removed but this may subsequently be removed by biological filtration, the use of Zeolite, some pH control methods or vigorous aeration. Reverse osmosis will remove salts through its permeable membrane but chloramines pass through easily and are not trapped or removed.

During partial water changes, or topping up for evaporation losses, chloramines are still added although their amount depends on the proportion of new water to the overall aquarium/pond water volume. Chlorine residual levels can be monitored during water changes; these test kits are available at aquatic dealers or, alternately swimming pool supply stores.

A Cautionary Tale…Posted 13 February 2007.

A fellow Koi keeper in my area decided to have a new pond. A pond builder quoted a completion date of 6 to 8 weeks. The Koi keeper therefore decided to keep his fish in his 1200 gallon Quarantine system, a bit small for all his fish but it’s only for 8 weeks. He was able to use his usual filtration system therefore the bio load should be the same as before. Within two weeks his problems started. He could not control the level of Nitrite. He added salt at ½ oz per gallon to ease the load on the osmoregulatory system of the fish. This reduced the nitrite level, not altogether to zero but acceptable according to his test kit. In the third week some of the fish developed what appeared to be blisters around the mouth, gills and belly. Within days these became full blown ulcers. The majority of these did not respond to topical treatments and some fish died.

A vet was consulted and he recommended a course of antibiotics. This seemed to stabilise the fish for a short time, then another fish died. By this time all the fish had become very skittish. A friend of his then noticed that on the bag of salt was the wording ‘anti-caking agent 535’. As this was purchased from a local Koi Dealer it was deemed to be safe to use. This may well be the case at normal cold-water temperatures, but the fish had been in the quarantine system at 24 degrees C (75degrees F).

The fish owner then looked on the Internet to find out what the ‘anti-caking agent 535’ was. To his horror this is what he found.

E535 Sodium Ferrocyanide
This translates to Prussiate of Soda.

According to the Food Industry safe for Human consumption and used in the food trade. There is no Dietary restriction, can be used by all religious groups, vegetarians and vegans.
It is prepared from hydrogen ferrocyanide and sodium hydroxide.

Function & Characteristics:
Used as a metal binder and anti-caking agent.

I offer you the following information taken from the Internet.

Sodium Ferrocyanide is the salt containing radical Fe(CN)64-(negative tetravalent); soluble in water but insoluble in alcohol. It is the main component Prussian blue pigment, Fe4 (Fe (CN) 6) 3, used mainly for the manufacture of inks and paints and bluing in laundry and dyeing. It is used for the removal of mercaptans (sulphur-containing organic compounds) from petroleum fuels and gas. It is used for making Sodium Ferricyanide (Red Prussiate of soda). Other applications include photography, tanning, explosives, metal treatments and snow treatment. It can be used as a food additive (anti-caking agent). It is important to know that sodium ferrocyanide is light sensitive, and cannot be exposure under sunlight.
On the Koivet site it states: Caution! NO YPS or yellow Prussiate of soda should be in the salt. Prussic acid is hazardous to fish because it dissociates into Prussic acid in water.

I leave you to make up your own mind on E535.

Ron Cooper

1. K.H.V. (Koi Herpes Virus) Warning....... Posted 10th march 2007 and August 2006

H.H.V. has been reported in fishing lakes and hoppyist's ponds in the south. Please make sure if you purchase Koi, you know of its reputable source and that you have a quarantine system in place.

The high summer pond temperatures have caused K.H.V. outbreaks in ponds which had previously thought to be safe, but had been dormant because of low temperatures.

Please go to the BKKS Web site for a fact sheet kindly provided by Dr. Paula Reynolds of Lincolnshire Fish Health.

For a recent Government announcement and information go to: www.practicalfishkeeping.co.uk/pfk/pages/item.php?news=1015

The following has been received from Rod & Gerry Isted and we list it for information;

Koi Herpes Virus

As a result of the very warm sustained weather in June and July (2006) with record pond water temperatures, we have seen a significant increase in the occurrence of Koi Herpes Virus (KHV) this year. Defra has reported 16 confirmed cases of KHV in the past two months in the UK's stillwater fisheries. However, we only hear about the reported cases to CEFAS and from our own work so chances are, this disease is much more common than most people are aware.

As a result of the seriousness of the disease, the Parliamentary Secretary for the Department for Environment, Food and Rural Affairs (Defra) and Junior Environment Minister, has recently announced in Parliament that it is his intention to make KHV a notifiable disease in the UK next year, bringing the disease in line with other serious fish diseases including Spring Viraemia of Carp (SVC) and Viral Haemorrhagic Septicaemia (VHS). At the present time, there is no known cure.

In the past, we have come across two cases of KHV in the past 6 years which we have discussed at the health classes..

At the present time, Gerry & I have confirmed four cases in the past three weeks in the South (end July/ early August). These have been positively diagnosed and not just guessed, using support from Real Time Polymer Chain Reaction Tests (PCR) which we have had run by our sub- consultant laboratory. The electronic results are with us within 48 hours (a bit of a change from the old 1 month DNA tests!!). Sadly, we have not been wrong so far with our site clinical diagnosis.

Testing for KHV has moved on very fast and the specialist laboratory we use is in a position now, through other tests, to detect your Koi’s exposure to KHV with limited confidence from the build-up of antibodies through blood samples taken on site. This avoids the need to sacrifice the fish. We have arranged for a German company who is specialist in blood & specimen collection, to send to us collection vials with caps changed to accept the smaller syringe needles we use with fish, so that we can undertake sampling if required.

Before we go any further with this article, I would stress that you should not be unduly worried or concerned at the present time. This article is not intended to alarm you in any way whatsoever but to keep you informed about what is happening at the present time, and suggested measures to take, to ensure that all your fish are kept secure. For this reason, we recommended that fish attending this year’s South Hants Koi Auction came from recognizable and safe sources and the vetting procedures undertaken was to safeguard your stock, should you wish to buy fish. The same applies to all club supported events. I am sure you will agree that this is the most responsible & secure way forward even if it means a few fish less at these events.

Recognising the Disease

KHV is considered a possibility if:

Only carp including Koi, ghosts and common varieties are affected. Other species such as goldfish etc remain unaffected.
Mortalities occur between 18deg.C to 30deg.C.
Mortalities are rapid. ‘Healthy’ fish can go down within 48 hours.
High mortalities often occur (60% to 95%)

"The symptoms of KHV are predominantly gill necrosis (gill disease and tissue die-back) but there are many other more easily-controlled diseases that can cause the same type of symptom. There are also many other ‘clinical signs’ quoted in the press but lets put these to one side as they can apply to many other ‘fishy’ ailments. We all agree that the symptoms are variable & changeable. Even some of us humans can have ‘sunken eyes’ after a long night on the tiles!

As the viral infection suppresses the Koi’s immune system, we always ‘swab’ immediately on day one of any undiagnosed mortality cases and our Vetinary Lab will identify within 36 hours, the bacterial pathogen/s and the acceptable antibiotics through sensitivity testing. As the immune system is depressed, we are finding that the clinical symptoms for KHV, as well as gill necrosis, takes on the form of the predominate bacterial pathogen. In normal circumstances, this pathogen is usually controllable by antibiotics, but not in cases of fish with depressed immunity.

How to ensure that your Koi remain safe

Only purchase Koi from your trusted dealer who is usually taking all precautions to ensure that you are supplied with a healthy Koi. Your dealer will ensure cross - infection risks are as minimal as humanly possible. In addition he will be able to flag up any health problem immediately as his biosecurity will create total traceability back to the supplying Koi farm. Talk to others in the Club if you do not have a regular supplier.
If you buy Koi from others, ensure that fish come from a ‘problem free’ source (ie another club member or friend who you know). We do not recommend buying Koi on ebay as we have already attended ponds where problems have likely stemmed from this source.
Ensure that the Koi has been correctly quarantined by your dealer. As ‘belt and braces’, we recommend you should undertake your own quarantining protocol. I have attached guidance which Paula (Reynolds – LFH) has sent to me with regards to her suggested protocol.
Think Bio-security
Keep your quarantine tank nets, bowls, equipment etc separate from the main pond
Do not lend equipment to others. If you do, ensure that they are thoroughly disinfected using an anti – viral product such as Vircon S or equivalent.
If you are at all concerned, talk to us or others experienced in health matters – we can always be reached on the phone (or leave a message if we are out).

QUARANTINE (note from Paula Reynolds – LFH)

KHV is not the only serious disease currently causing concern in Koi and it is now vital to isolate all newly purchased Koi to protect your existing pet fish from all types of disease including KHV. There is no foolproof method of initiating disease during quarantine however heat cycling is the best possible safeguard. The water temperature at the outset of quarantine will vary with the ambient temperature depending on the time of year but the need for heating equipment is unavoidable. The difficulties of achieving low temperatures in summer are obvious and for most hobbyists this will require frequent water changes via purification equipment. However the lower temperature is critical. The drawback is that the Koi must be constantly monitored no matter how gradual the temperature changes are carried out to ensure parasites such as whitespot are not becoming a health problem. Many Koi naturally carry whitespot without any sign at all until a change in temperature acts as the trigger for an outbreak.

At the outset of quarantine the water temperature should be held at 15/16C for 24 hours then very gradually increased over approx 7 days to a minimum of 23C maximum of 27C and then held for 3 weeks. The temperature should then be taken back down slowly to 15/16C for another 24 hours and again with care not to stress the Koi taken back up to a maximum of 27C and held for another 2 weeks. If disease of any kind has not developed in that period it is possible that the Koi have never been exposed to serious disease such as KHV. If hobbyists are still concerned enough to want to repeat the process let the Koi recover for a few weeks first. Ensure they are free of parasites and well fed before carrying out the cycle again.

There is no time scale for the quarantine period as it will vary with the Koi-keepers ability to control the temperatures and the health status and reaction of the Koi. However 3 months is considered viable. On the day the quarantine period is finally over it is vital to ensure that the water parameters in the quarantine facility mirror those of the pond, the p.H and temperature are especially important. Having taken the Koi through a potentially stressful quarantine the move to the main pond must minimise the stress associated with any change of environment.

And Finally,

We do realize that the quarantine procedures advocated by Paula are very rigorous and sometimes not practical to the hobbyist. We are not saying that you all need to follow this but you should ensure that your fish have undergone a heated quarantine protocol at some stage. This is usually carried out by your trusted dealer – but check.

Koi-Keepers can be assured that progress has been made within the industry in understanding KHV through all sorts of scientific studies. The hobby can still be enjoyed by all as long as the current health risks are acknowledged and quarantine is accepted as an integral part of keeping Koi.

We are not saying anything new but reiterating what we have covered in the health classes over many years, namely:

Buy your fish from a trusted source
ensure that quarantining has been undertaken.

Should you have any concerns whatsoever or wish to discuss any aspect of this note or have any questions you wish to raise, then please do not hesitate to contact us.

Rod & Gerry Isted

Health Consultants

16^th August 2006.

01243 572762 or 07726840627

The following is part of a BKKS message posted on message boards;

It is known that a dealer at the National has contracted KHV since the show, but there is no evidence that it was caught at the show, in fact it seems most unlikely, and no other dealer or hobbyist who attended with fish has reported an outbreak of KHV since the show. It is most likely that a carrier was triggered by the low vat water temperatures at the National (15-16c) followed by a rise in temperature on returning home. This should also have triggered any other cases if they existed, and nothing has been reported. Please be assured that the BKKS will do everything possible to ensure healthy fish arriving at a show also return home healthy.

Peter Robbins & Rod Taylor BKKS Officers

2. Basic Do's and Don'ts for Koi Fishkeeping

ACCOMMODATION

Do site your pond close to the house, avoiding overhanging trees or soil washing into the pond or other occurrence that

could be detrimental to water quality.

Do ensure your pond is deep enough - at least 5ft (1.5m).

Do ensure the pond is free of any projection or over-hang that could damage fish.

Do your initial pond filling through a water meter so you know your total gallonage in case you need medication.

Do have an adequate filtration system on your pond.

PURCHASING and STOCKING LEVELS

Do find a good koi dealer (one you can trust) and buy only from him.

Do ensure fish look healthy with erect fins that are not torn or split. Scales should lie flat and there should be no sores, holes,

abrasions, signs of fungus, disease or parasites apparent.

Do check the underside before buying; this can be done in a plastic bag.

Don't buy koi with sunken or protruding eyes or with large heads and thin bodies.

Don't buy more fish than your quarantine system can cope with.

Don't overstock your pond.

Don't introduce new fish into your pond without quarantining.

Don't introduce too many fish into your pond at once as the filter will not cope straight away.

POND CARE and MAINTENANCE

Do test your water quality weekly. Test temperature and for pH, ammonia, nitrite and nitrate. Test daily if you have a problem

or if it is a new pond. Note: temperature, pH and ammonia toxicity are all related.

Try to keep a log of your test results for future reference.

Do make regular water changes, perhaps 10% daily in the summer, and small changes in the winter but beware

of reducing the pond temperature.

Do keep the pond clear of debris. A net may be used to keep out leaves in the autumn; it may also deter cats and herons.

Do provide aeration with a venturi, air dome, air stones, or waterfall - especially in hot weather.

Do observe your koi and their regular habits - change can sometimes indicate ill health.

Do isolate sick koi from the pond for closer observation and treatment, but ensure they have company in hospital tanks.

Do ensure your pond has no rapid changes in pH and temperature.

Don't use unfiltered mains water in your pond. Use a water filter that is specified a fish-safe.

Don't use pesticides or weed-killer near your pond. Ask your neighbour not to spray when it is windy in case any

chemical gets into your pond.

Don't medicate your pond unless you are sure what your problem is - flashing may be parasites.

Don't medicate as a regular preventive measure.

Don't smash ice on the pond, but ensure there is adequate ventilation to remove gases. Boiling water may be used to make

a hole safely. Floating pond heaters are useful in prolonged cold spells. Consider installing a pond heater.

Don't switch off your filter during the winter months.

FEEDING

Do feed koi little and often.

Do ensure pellet food is fresh and kept in an airtight container in a cool and dark place.

Do feed your koi a varied diet.

Don't overfeed.

Don't feed when the pond temperature is below 10 degrees C or 50 degrees F.

________________________________________________________________________________

3. PARASITES & TREATMENT

Parasites How to identify and deal with those nasty little unwanted guests ! The Macro parasites - Argulus, Lernaea, Gyrodactylus and Dactylogyrus. The Protozoans - Trichodina, Costia, White Spot and Chilodonella<	The following information on Koi parasites and treatment below is with grateful acknowledment to the Chiltern Koi Club

Treatment is by manual removal of the parasite with tweezers under anaesthetic, ensuring that the whole parasite is removed. To be sure of complete removal, dip a cotton bud in strong potassium permanganate solution and dab the worm with this solution whereupon it will release its grip immediately. Pond treatments include Dimilin or Paradex	Lernaea - Anchor worm (shown left) is a common parasite on our koi which is clearly visible to the naked eye and can reach 10 to 12mm. The parasite burrows its head into the koi's tissue, under a scale and only the body and tail are normally visible. If left on the koi, secondary bacterial infections can occur at the point of contact due to the damage caused by the anchors used to attach itself.. Lernaea lay eggs which can lay undetected in the pond and can hatch when conditions and water temperatures are right. Chemical treatments will not affect the viability of eggs so repeat treatments may be required to kill all generations. Normally the parasite attaches itself by the dorsal or tail fin, and is also commonly found in large numbers on the bellies of koi when they are first netted from the mud ponds.
Dactylogyrus - The Gill Fluke.(right) Gill and Skin flukes are two of the family of monogenetic trematode genera, all of which are characterised by the large grappling hooks which are used to attach themselves to their victims. Flukes are another common parasite affecting our koi are are both egg layers and live bearers. They range from 0.05 to 3.00mm long and there are actually a huge number of species in the genus Affected koi often exhibit classic signs of irritation and flash or rub themselves against objects in the pond in an attempt to rid themselves of their attackers.
	Gyrodactylus - The Skin Fluke. (left) Koi suffering from infestations of gill flukes may suffer respiratory problems as the flukes begin to damage the delicate gill tissues. Secondary bacterial infection often occurs in koi left suffering from these parasites, due to the physical damage caused by the anchors. Chemical control of both types of fluke can be achieved with Chloramine T, Malachite Green Formalin and Masoten, or Potassium Permanganate. In order to kill all generations, repeat treatments may be necessary, the frequency being dependent on temperature and chemical used.
Argulus - The Fish Louse (right) It is said that this parasite can be commonly introduced into our koi ponds by frogs and toads. It is however easy to detect with the naked eye especially against the background of fins and white skin of affected koi. Size varies from between 1mm and 5mm. Attaching themselves to the koi by suckers which damages the skin, they also inject a poison into the body of the koi which causes inflammation, bleeding and potentially secondary bacterial infection. Chemical treatments recommended to eradicate these parasites are either Masoten, Dimilin or Paradex.	Repeat treatments may be necessary to ensure that all generations of the parasite are killed.
Once dead, the host is quickly deserted by the parasites who swim off in search of new prey. Affected koi may show classic signs of flashing and rubbing, may hold their fins clamped against their body and appear listless. They will also hang at the pond surface and gasp for air in severe infestations. Recommended treatments include Malachite Green and Formalin, Potassium Permanganate or Salt baths at 3% ( 4 and one half oz. per gallon )	Chilodonella (shown left) Chilodonella is classed as the most dangerous of the Protozoan parasites and can cause mass fatalities especially in overstocked ponds and aquaria. It is between 40-60 microns in diameter and can be easily identified on a microscope slide using 100 x magnification. It reproduces itself by transverse fission, and the adult has a heart shape appearance, although this is changeable, and its body is evenly covered with cilia. The parasite can actively swim short distances so healthy fish are easily infected. An infestation of Chilodonella can cause opaqueness of the skin, especially between the head and dorsal fin and in severe cases the skin can look swollen. Gills are also attacked and can be totally destroyed, quickly killing the host.
Costia (shown right) Costia is a minute Flagellate with 3-4 flagella. It affects both the skin and gills of koi, and reproduces itself by binary fission. Infestations of this parasite can appear very rapidly indeed, and koi suffering infestations exhibit the classic symptoms of lethargy, clamped fins, rubbing and flashing and the skin can take on a grey white opaqueness. Costia normally only affects fish that have already been debilitated by some other cause, and can often be seen on koi as a secondary parasite. A high magnification must be used to view these parasites (300 x) and staining is recommended for positive identification.	Costia is classed as a cold water parasite and is not normally able to survive temperatures in excess of 85 deg F. Recommended treatments include Potassium Permanganate, Acraflavine and strong salt baths of 3% ( 4 and one half oz. per gallon )
A magnification of 100 to 200 x is required to view this parasite. Recommended treatments are Potassium Permanganate	Trichodina (shown left) Trichodina is one of the easiest protozoan parasites to detect under the microscope as it is almost perfectly round with hundreds of hooks which resemble cilia found its periphery and it constantly rotates as it moves through the mucus, causing tissues damage. It attacks both skin and gill tissues of our koi, and can often cause more damage to gills than realised. Classed as a warm water parasite, it can survive for some time without a host. It causes vegetation of the skin giving rise to a grey white opaque appearance on the body of infected koi which exhibit the classic symptoms of flashing, rubbing and lethargy.
White Spot (below and right) Ichthyophthirius multifilis (Ich) - White spot , one of the ciliates, showing the classic horseshoe shape macronucleus (above) is classed as a large protozoa, which can be detected by the naked eye on infected fish by the appearance of hundreds of tiny white spots where the parasite has bored through the skin of the host. The adult parasite drops off the host, surrounds itself with a capsule and fixes itself to a plant or rock. Inside the capsule the parasite divides and multiplies and eventually 250 - 1000 tiny 'swarmers' are released and these then swim off in search of a new host. The swarmers typically attack the dorsal and caudal fins of koi, although gills and body are also affected. The swarmers burrow through the surface of the skin and so the parasite resides in the body and not on the body of infected fish.	White spot on microscope slide The complex nature of the life cycle of white spot can render it difficult to treat as it is only the free swimming swarmers that can be killed with chemical treatments. Once the swarmers attach themselves to our koi, until they detach as adult parasites can take between 4 days at 27 deg C (80 deg F) and up to 4 to 5 weeks at 10 deg C (50 deg F). The parasite becomes encapsulated in only one hour after leaving the host. Newly produced swarmers can however only live without a host for up to 55 hours maximum, so by simply removing koi from a pond for three days, it can be cleared of the parasite completely.
White spot swarmers (right) Chemical treatments have to be long lasting and repeated several times to rid the fish population of these parasites. Recommended treatments are Acraflavine, Malachite Green and Formalin, and prolonged use of salt at one half oz per gallon. Chemical treatments should be repeated at least twice to ensure complete eradication.

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.

Pond temperature
Pond pH.
Pond inhabitants
Condition of koi to be treated.
Single or multiple parasite infestations
Condition of your filters.
Manufacturer of drug.

Let’s try and explain.

Pond temperature
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.
Pond pH
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.
Pond inhabitants.
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.
Condition of your fish.
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.
Single or Multiple infestations.
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.
Condition of your filters.
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.
Manufacturer of drug.

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:

We don’t know the correct volume of our pond
We ‘guess’ at the identity of the parasite (i.e. no scrape to check) or worse we wrongly identify the parasite detected. This is all too common as some of the Protozans look very similar.
We use a chemical which is inappropriate for the pond temperature (or pH)
We use the wrong dose (don’t check the strength) – or simply can’t measure it accurately!
We only use one treatment or use two at the wrong frequency to catch the life cycle.
We forget to switch of our UV – thus causing the chemical to break down too quickly in the water

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!

4. Spring Care - Suggested Husbandry (With acknowledgement to Chiltern Koi Club)

1. Large ponds will benefit. Use covers through spring with smaller ponds.
Spring has arrived, and with our fickle climate in the U.K., this can mean that temperatures can vary enormously almost from day to day and temperatures at night can be at or near 0 deg C until the end of April.
This is where those of us with large deep ponds will benefit over small shallow ones, as daily temperature fluctuations will be minimised.
Small ponds can give rise to substantial fluctuations in Spring temperatures and it is therefore a good idea to provide a cover of some type to use at night to help prevent rapid water temperature changes.

2. Take care when beginning to feed
As we have seen above, rapid temperature changes can occur in smaller ponds. Be mindful of this when beginning to feed, and do not start feeding until temperatures have reached between 50 - 52 deg F.
If your pond has a larger volume, with a more staple temperature profile, you can start feeding sparingly at a temperature slightly less than this.
Only use wheatgerm foods, or a modern all the year round food which is designed to be used at low as well as high temperatures.
Your koi appreciate a stable environment. They can withstand a broad range of temperatures, pH levels, and even pollutant levels if stable. They DO NOT like rapid changes in temperature or pH especially. If you have a small, shallow pond, these parameters are more likely to fluctuate quickly. Larger, deeper ponds provide a better, more stable environment for your koi, specially during the winter and spring seasons.

3. Water Quality
Your filters will have been 'just ticking over' during the winter period, owing to the lower water temperatures, and low levels of ammonia being produced by the koi during this time. However, as the water begins to warm up, and you commence feeding, your filters will start to work more effectively in response to warmer water and higher ammonia levels.
You must take care not to overfeed during the spring, since not only will your koi not require large quantities of food at this time, but uneaten food will decay and this may increase ammonia levels before your filters can cope with the extra load.
To guard against filter 'lag'. ensure that you test your pond water regularly at this time of year, especially for ammonia and nitrite, the two most toxic pollutants.
If you find that levels of these two pollutants have risen to unacceptable levels, stop feeding immediately and carry out regular 10 - 20% water changes (using a water filter) to lower the levels of these substances in the water.
Salt may also be added at the rate of 0.5 oz per gallon as this is a good general tonic for you koi, but also reduces the affect of nitrite poisoning.

4. Be Observant
Spring is probably the most nerve racking time for all koi keepers, as most problems which occur do so at this time of year.
By observing your koi and their behaviour, especially at feeding times, you will learn to recognise any problems at an early stage and take appropriate action.
Do not be tempted to use prophylactic treatments at this time of year, your koi need excellent water quality, and adding chemicals to your pond unless absolutely necessary is definitely not a good idea.
In addition, many pond treatments do not work well at low temperatures and are therefore much less effective.
Your koi's immune system is effectively switched off during the winter and will not start to work until the water temperature has reached around 12.5 deg C.
As many parasites and bacterium are active and reproducing at temperatures lower than this, if your koi are affected by parasites or bacterial diseases, they will be much less able to fight off any infection or parasite attack and so spring is the time of year when your koi are more vulnerable to opportunistic attack by both parasites and bacteria.

5.Overcoming health problems
Don't panic !
If you suspect your koi are suffering from parasites you should attempt to identify the culprit before treatment.
Catch one of your suspect koi and take a skin scrape and examine this under a microscope (our club hires these out to members) to determine which parasite, if any, is present.
Once identified, you can then apply the appropriate remedy knowing that you are treating a known problem.
If you suspect a bacterial infection with one or more koi generally the symptoms will be visible to the naked eye.
Koi that have damaged themselves or been attacked by parasites are liable to have open wounds on the body which may become infected by pathogenic bacteria. Normally the affected wound would become ulcerated if left unattended, and an appropriate remedy should be administered as soon as possible if the wound is infected.

6. Treating your Koi

Suggested treatments - Common parasites.
Anchor Worm - Dimilin.
Skin Flukes. - Malachite Green and Formalin.
Gill Flukes. - Malachite Green and Formalin.
White Spot. - Malachite Green and Formalin.
Trichodina. - Potassium Permanganate.
Costia. - Potassium Permanganate.
Dosages - Follow manufacturers instructions.
Dimilin and Potassium Permanganate can be used at any temperatures.
Malachite and Formalin. are not affective at temperatures of less than 10 deg C.
Switch off UVs during treatment
Suggested treatments - Bacterial and Fungal diseases
Fungus - Malachite Green or Elbagin.
Wounds - Potassium Permanganate or Chloramine T to disinfect water and kill bacteria.
Ulcers. - As above for wounds. May need antibiotic treatment - should be administered by a qualified vet or club health officer. Separate from other koi if possible. Provide heated quarantine tank to speed recovery.
NB. Use salt at 0.5 oz per gallon as a supportive treatment in the pond or quarantine tank.
Note that these recommended treatments are by no means the only ones available. If you have a treatment regime that works for you for any particular condition above, please don't change !

DO NOT OVERDOSE