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Point of view       (Points of View - the Tetra series)


I wrote the following articles for Koi Magazine.
Therefore they own the copyright but the Editor has given permission for them to be republished here.

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A series of six short articles commissioned by Tetra for publication in Koi Magazine


1. To treat or not to treat

If a child was unwell, would you suggest going to a pharmacy and browsing the shelves for a treatment that best fitted the child’s symptoms?  If that produced no improvement, would you suggest trying a different treatment and doubling the dose?  Of course not, a sick child should be properly diagnosed before any treatment is administered.  We shouldn’t treat koi that way either, first trying one treatment, then another. Koi, like sick children, should be properly diagnosed before treatment.  So where should we start with a sensible approach to diagnosing a sick fish?

Post it Tetra treat or notPoor water quality can cause koi to exhibit similar behaviour to a typical symptom of a disease or infection.  For example, koi that are flicking might not be suffering from a parasite infection; they may be being irritated by poor water. Koi gasping at the surface may not have gill problems, they may be trying to shout: “Get me some air-stones, I’m suffocating!” The first step in diagnosing whether or not they are sick is to make sure that the water is of acceptable quality.  Improve the water and they may suddenly get better! Even if water quality is not the problem, it is no more realistic to expect a fish to recover from a disease in poor water than to expect a sick child to recover in a bad environment.

If the water is good, what next? This is where experience counts. Proper diagnosis means finding the cause, not treating the most obvious symptoms. Fungus may be the most obvious symptom, but it won’t be the root problem, it is a secondary infection that gains entry through broken skin.  Inexperienced koi keepers should seek the help of someone more experienced who could advise if, for example, a scrape or close examination might help identify a parasite as the initial problem. Then the most effective treatment could be given.

An experienced person could topically treat wounds or ulcers but they will realise where treatment is beyond their abilities as is the case with bacterial infections.  It is no longer legal for just anybody to obtain antibiotics and start poking koi with needles. A veterinarian must be called out to diagnose the problem.   If antibiotics are needed, they can decide which will be most effective. They can administer it also and assess whether the owner is capable of injecting subsequent doses. Vets aren’t cheap, but if you wouldn’t try random treatments on a child, you shouldn’t randomly treat your koi. 


2. Preventative treatments

If I have a headache, I take two Paracetamol and they “cure” that headache, but is that a good enough reason to advise everyone to take regular doses of Paracetamol to prevent the onset of future headaches?  Medication is valuable for treating ailments that actually exist, but we can take preventive medicine too far. This does not mean that some preventive treatment is not desirable though.

Post it Tetra preventative medicine02Dave Wolfenden’s introduction to this topic [see Koi magazine, issue 146 p 66/67] refers to prophylactic treatments for new koi. “Prophylactic” has a dual meaning; it can be either an actual treatment or a preventive measure.  Quarantining new fish is the most sensible preventive measure. Recommended quarantine regimes include “heat ramping”.  The principles are well known and need not be described here other than to say that the fish should be kept in isolation while subjecting it to stress brought on by temperature variations and that the original aim was to trigger latent KHV, if it existed. Stress also reduces the immune system, so if a fish was carrying a significant parasite infection, the parasites may be able to take advantage of the stressed immune system and multiply. Whilst it would be going too far to treat new fish for every known parasite, just in case there was the odd one hidden in the gills for example, it is a sensible preventive treatment to give koi a salt bath, after allowing a day or two for it to recover from the stress of transportation, but before the heat ramping quarantine period begins.

Having successfully completed the quarantine regime, new koi can safely be released into the pond to join the existing residents.  Should any preventive treatments now be added as a matter of course? I would suggest not. This is where prophylactic measures, not treatments should be employed. Good pond husbandry and attention to water quality are the best preventive measures to adopt.  Random treatments with aggressive chemicals are just as likely to do harm as they are to do good.

Pond treatments such as Envirex and products containing beneficial bacteria that out-compete harmful bacteria are good preventive measures rather than random treatments since the aim of these products is to promote a generally healthy environment rather than to treat the fish themselves. However, if a treatment is specifically designed to cure an ailment rather than to just improve the environment, I believe that treatment should only be used if proper diagnosis shows that it is necessary.


3. Showing koi

To comply with animal welfare legislation, it is essential when showing koi to get them to the show safely and without causing them undue stress.  Apart from the cruelty aspect if fish are not properly treated, damaged or dejected looking fish would neither win prizes nor will they be a credit to their owner. It would also give the impression to onlookers that the welfare of our koi has not been given proper consideration.   Netting fish is an art but one which is easy to master once the correct method has been demonstrated.  If in doubt, ask! Bagging and transporting fish also should be simple but this is where harm could occur if not done properly.  It is important that there is enough water in the bag to cover the gills but the rest of the bag should be full of air or preferably oxygen. More water in the bag than is necessary will reduce the amount of air available.

Post it Tetra showing KoiIf you will be taking a long time to catch all the fish you intend to show, spare a thought for the first ones that you catch. Don’t leave them in bags in the sun whilst you catch the others, the temperature in the bag will soar, the dissolved oxygen level will plummet and the fish could be in serious trouble before you even get them into the car.  Floating nets are not expensive. Koi could be netted at a leisurely pace, then transferred to the floating net and only bagged up once they have all been caught. Doubled bags, each bag sealed with a separate elastic band, are essential.

To protect the fish and also reduce stress, the bags should be transported in appropriately sized strong cardboard boxes or purpose-made boxes that will shut out much of the light and also give the fish the impression of being safely enclosed.  Fish do not like to feel exposed and vulnerable, so this will have a calming effect.  Larger koi should be loaded so that they face across the car, ensuring that they don’t damage their mouths or tails during acceleration or braking.

It is not only our legal duty to ensure the welfare of koi during transport, it should be a moral priority to look after our pets and ensure their safety.


4. Koi and winter feeding

Have you ever seen notices alongside natural lakes warning the fish not to eat when the temperatures are low?  Me neither. Yet still throughout koi keeping circles there are warnings that feeding your koi when water temperatures are lower than 10°C will do them harm or possibly kill them.  Fish in the wild are not constrained by such thinking.  Obviously their appetite will be much less in winter than in summer but they eat when they want to eat and they have been doing this since fish first evolved.  To understand why fish need to eat during winter it might be easier to first understand what happens to the food they eat in summer.

Post it Tetra winter feedingCarp are omnivorous; they will eat whatever they can find. The food they find to eat in summer will include a good proportion of small aquatic creatures such as bloodworms, insects and insect larvae. These will be high in protein. Protein is required for growth, so part of this food will go towards increasing the fish’s size.  There will also be some plant material which is a source of carbohydrates. The residual protein and the carbohydrates are used as a source of energy. The greatest demand on this energy source is the energy used for swimming.  There is also energy that is used for simply staying alive. The heart needs energy for every single beat, the gills need energy, even the optic nerve requires a small amount of energy to transfer light into the brain in the form of electrical impulses.

In winter, metabolism is slower, growth ceases and the energy expended in swimming is very small but this energy and the energy required to stay alive cannot be disregarded. In winter, wild carp will occasionally feel the need to find something to eat. With no high protein insects about, they will eat the odd scrap of plant material. In a pond in winter, if this small amount of energy is not replaced by feeding, it will be replaced by burning stored fat.  As this is depleted, energy will eventually have to come from burning muscle protein to stay alive. Over an extended period without food, your koi will be slowly wasting away.

Be sensible about winter feeding.  Wheat-germ with low protein content is the obvious choice for koi during winter. Offer small amounts but only when they are obviously hungry and remove any that is not immediately eaten.


5. Carp pox

The semi-translucent, lumps resembling blobs of candle wax that spontaneously appear on koi are commonly known as carp pox.  Carp pox is the visible symptom of the herpes virus, Cyprinid Herpesvirus 1, or CyHV-1.  It is closely related to CyHV-2 which causes similar symptoms in goldfish and also to CyHV-3 which is more often called KHV. All these viruses are totally separate and it should be emphasised that a fish with carp pox is in no danger of contracting KHV unless it has also been exposed to KHV. All are incurable and symptoms will frequently appear after periods of stress.   Carp pox symptoms sometimes occur after winter in unheated ponds and often disappear as the fish grows to maturity.  If bacterial diseases can be cured why is it that these viral diseases cannot?

Post it Tetra carp poxTo understand why viral diseases such as carp pox cannot be cured but bacterial diseases can be cured, first consider how human beings function. We are born then have to take on nutrients (eat) and reproduce before we die. We call this process life. Bacteria are simpler life-forms but they behave similarly. They are alive.  If we can interrupt their life processes or if we can terminate them prematurely, it is possible to end or to cure a bacterial infection.

Viruses are completely different.  They do not follow processes that could be described as living, therefore they cannot be killed.  The carp pox virus, in common with other viruses, is far smaller than a bacterium and consists of a piece of genetic material such as RNA or DNA. It cannot reproduce by itself, but can insert itself into the cells of its host. As these infected cells reproduce making copies of themselves, they also make copies of the virus within them. These new viruses then go on to infect other cells.  It is possible to destroy a virus before it infects its host’s cells but once it has infected them it becomes impossible to destroy it without destroying the host cells. In other words, a treatment that would destroy the carp pox virus would also kill the fish it has infected.

The koi immune system can recognise that an infected cell is behaving oddly and destroy them, one at a time, without damaging uninfected cells.  This is why some treatments claim to cure carp pox but these are usually immunostimulants that merely boost the immune system to help it combat infected cells.


6. Treat foods

Treat foods, are they a treat, are they necessary, or for that matter, can they be harmful?  Disposing of the last one first, it is obvious that if a koi keeper literally throws anything they can find into the pond then there is a risk that occasionally they will inadvertently do harm.  A forum post, (on this magazine’s forum I think), described how one koi was fed a large slug which it managed to swallow but which was too big to pass through its gut. It stopped eating and became unwell as the slug decomposed inside it.  Fortunately, after a few days, a mess emerged that had once been a slug and the fish recovered, so all was well in the end but we must recognise that badly chosen treats might be harmful and we should stick to the tried and tested ones.

Post it Tetra treat foodThat leaves the question; are they a treat or are they necessary?  If we feed good quality food then treats may not be necessary for the fish’s diet because the manufacturer will have ensured that their food will provide all nutritional requirements, but even then, arguably, treat foods are still necessary to provide the interaction between the pet and its owner. Interaction with an animal is what turns it from a possession into a pet and koi should not merely be a possession. We are also in charge of their welfare, and hand feeding treats allows us to monitor their behaviour and general condition.

So, treat foods can be harmful if badly chosen, they are necessary if only for interaction, but are they actually a treat?  Fish behaviour suggests so. They make choices as to what they like and what they don’t, choosing by smell and taste. Living in water, their sense of smell is like being able to taste from a distance.  This allows them to home in on food that tastes nice, even in murky water. Fish have taste buds on their lips as well as inside their mouths giving them a second opportunity to taste food by bumping into it before eating it.  A third tasting is done as they eat and fish will spit out what they don’t like. Knowing this and watching fish enthusiastically eat one kind of food or swim up to another kind and reject it implies that they are making sophisticated choices about what to eat and that they clearly regard some foods as a special treat.


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