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Chris on Koi

Chris NeavesChris on Koi articles are reproduced with the kind permission of Chris Neaves and have been published all over the world. Of one thing you can be sure: these articles will expand your knowledge and positively grow your confidence in your own koi keeping abilities in an instant!

Chris started collecting Koi in 1972 and in 1988 he became a founder member of the South African Koi Keepers Society (SAKKS). uring 1988 and 1989 Chris served as Treasurer of the SAKKS and from 1990 to 1992 as National Chairman, also chairing the 1st and 2nd SAKKS National Koi Show Committee. During the five years that Chris was Treasurer and Chairman he also took on the responsibility as Editor of KOISA.

They say that once Koi fever hits you, it hits you badly.  Since 1988 to date, Chris has researched and written four books on Koi and related subjects for the enthusiast.  He also authored articles and essays on Koi and water features / ponds in magazines published in Japan, the UK, America and South Africa.  He further contributed to the Koi book published by Jonathan Ball entitled Living Jewels, researched and wrote the original basic study manual for Training Koi Judges which has been reviewed and up graded by the present Judges’ training committee.  In 2001 Chris was appointed by the Associated Koi Clubs of America to write study modules on filtration and nutrition for training Koi Health Advisers (KHA) in Canada and the USA.

In 1990, Chris went on a sponsored trip to Japan to purchase show grade Koi and breeding stock for South African enthusiasts, further contributing to the increase in quality of Koi in South Africa.  From 1990 to 1993 Chris ran an import agency for Koi fish, importing high grade and show grade Koi fish for collectors, retail dealers and breeders.

In 1993 Chris represented koi keepers at a government enquiry into the possibility of banning Koi imports into South Africa.

Chris developed and still markets Shogun Koi Nutrition and Shogun Tropical fish food since 1995, and since 1992 owns Shogun Consultants who do consultations on all aspects of Koi and water features to individuals, architects and corporations.

Chris can be contacted by e-mail at This email address is being protected from spambots. You need JavaScript enabled to view it.

A Case Against Anti-Biotics?

Note: This article was first written in 1996 and published in 1997. Many experts disagreed with this article and Chris came under some harsh critism. The outbreak and first reports of of the devastating Koi Herpes Virus occurred soon after this.

“The World is unprepared for the coming plagues” says Laurie Garrett in her recently published book - The Coming Plague - which documents the fight-back microbes are making on the planet. After four decades of assuming that the conquest of infectious diseases was imminent, people on all continents now find themselves besieged. Doctors and scientists have been fighting a fifty year battle with infectious microbes. In recent years strains of TB, cholera, malaria that are resistant to all known anti-biotics and drugs have sprung up all over the world. New bugs and viruses that kill in hours have been recorded in recent years.

Bacterial infections were a common and serious problem before the first antibiotics became available in 1944. After the introduction of penicillin at the beginning of the war, a minimal dosage would perform miracles. Today massive dosages of any number of anti-biotics are needed in many cases. In those days there was very little understanding of what the tiniest microbes, viruses did to the body. There was no distinction made between bacteria and viruses.

Last Updated on Thursday, 15 March 2018 15:16


A Drop in The Ocean?

Have you ever thought about the almost insurmountable problems in making a pond waterproof? Is a completely waterproof pond an impossible dream? Substantial leaks need attention, no doubt about it. However, at some point or the other, insanity will overcome you, before each and every leak is found and fixed in the average pond.

The three primary sources of leaks are - waterfalls/streams, pipework, incorrect sealing. Waterfalls are a major culprit for leaks. Any splashing, no matter how minor, will result in water loss. Added to this is the reality that waterfalls or water courses develop hairline cracks between rocks and cement at some stage or the other. There is also natural evaporation to be taken into account as well.

But my pond goes down several centimetres each day - there must be a massive crack in the floor. How can tiny hairline cracks around pipe work or in the waterfall together with splashing loose substantial water from your pond you ask? Yes, definitely. If a single drop of water leaks out of your pond each second you will lose about 3.5 - 4 millilitres of water each minute. This is 240 ml per hour or 5,7 litres of water each and every day of the year. That's over 20,000 litres a year.

Last Updated on Friday, 31 October 2008 12:09


Bursting Bubbles

The life functions of koi are similar to that of other animals in that they have muscles, skeletons, skins and internal organs which function in approximately similar ways. There is however, one great difference between fish and animals - fish live in water. More importantly to our circumstances, koi in ponds live in a limited volume of water.

A limited volume of water means that there is no continuous incoming freshwater source as would be found in a mountain stream for example. The only water available to our koi is what is in the pond.
This may sound like grade one logic, but we must keep this fact in mind - all the time. A koi's body is composed of about 80% water, much the same as ours. Therefore, koi are literally sacks of water separated from the pond water by a membrane (it's skin)! Thus to understand what water means to a koi is to lay the foundation for a more complete understanding of what a koi needs to survive. Any changes in the pond environment (water) will have an immediate affect on the koi. The greater and more sudden the change the less likely the koi will be able to adapt and the less likely it will survive. Transferring koi directly from one pond to another with a temperature change of more than 3 or 4ºC can cause thermal shock and even death.

Last Updated on Friday, 31 October 2008 14:23


Dynamics of a Koi Pond

Water is a very remarkable substance. Without water life would not exist on earth. The extraordinary properties of water have a direct bearing and influence on the daily existence of our fish. A fishes body is composed of more or less 80% water. So it is easy to envisage fish as a volume of water (its body) separated from a volume of water (the pond) by a thin membrane (the skin). The most insignificant changes in the pond environment will therefore, have a direct and almost instantaneous influence on the life of our fish.

The pond itself is literally a living entity. The factors that influence the water dynamics and parameters ebb and flow through out the day as well as throughout the seasons. Each and every one of these Influencing Factors, lets call them - IF’s - is dynamic. This is very important to remember when dealing with pond situations and perceived koi problems. Sometimes we create problems which are not really there. During the course of a 24 hour day each IF (Influencing Factor) has a natural dynamic change. These dynamic variations can be recorded and a daily pulse or oscillation can be observed. As the seasons change so do some of the parameters - the most obvious is temperature from the summer months to the winter months. A pond or water system has a natural bio-rhythm of life which fish have adapted to over many millions of years.

At any point of time, during the day or year, a measurement of one or the other IF will be different when compared to another measurement taken at a different time of the day or year. These fluctuations or dynamics should never be viewed in isolation. A single reading on a test kit will present a distorted view of what is actually going on in your pond. You may be panicking for nothing.

Last Updated on Friday, 31 October 2008 11:39


Filtration Facts and Fiction You MUST Know - Slime City


When we enter the hobby of koi keeping we soak up as much information as possible. Much of this information has proven to be not entirely correct. Some of the information we are given has been misinterpreted and distorted. As science progresses and new discoveries are made so we must recognise them and adapt then to our hobby.

In previous articles in this series we have looked at some interesting facts and concepts surrounding filtration in Koi ponds. In this essay we turn our attention to one of the most important parts of the whole pond system - the media.

Whilst bacteria grow on all surfaces of the pond, the purpose of a biofilter or bioconverter is to provide an extra locale that will increase the surface area for nitrifying bacteria to grow on. We do this because the stocking densities in our ponds exceed that of a natural environment. Interestingly, in nature, the nitrifying bacteria will seek out areas where there is a food source concentration (ammonia) and colonise this area. By creating a chamber (or chambers) packed with a media of some sort (extended surface area) and by pumping the pond water through this area, we are, in reality, concentrating the ammonia etc. into this space. These are exactly the things found naturally in nature where nitrifying bacteria flourish - an increased surface area for bacterial colonisation and a feeding area of easily available ammonia for the bacteria.

Last Updated on Saturday, 19 September 2009 21:32


Flow Rates - Let The River Run

Just how critical are flow rates to successful koi keeping? And what about circulation, is it really necessary to move the water within a pond? There are a surprising number of common maladies koi keepers experience with their koi and water quality that can be easily remedied with a change in flow rates and circulation patterns.

Our ponds are amazingly similar to the human body. Flow rates and circulation are critical to a pond and the human body. Circulation dissolves oxygen and impurities evenly throughout the pond. Circulation in the body provides oxygen, removes carbon dioxide and metabolic waste. Fresh water from the filter is quickly dispersed throughout the pond, diluting the existing water being polluted by toxic waste and degrading organics. "Fresh" blood from the liver, kidneys and lungs (the bodies filters) is pumped to every corner of the body into each and every cell to sustain life.

A pond with a large water volume, but a limited number of koi, can have a slow turn over / flow rate. The larger volume of water is a natural buffer against rising toxic waste levels. The large volume of water (relative to stocking densities) has a reserve capacity of oxygen. However, as the fish biomass increases we have to make adjustments to maintain health and water clarity. We either have to increase the water volume or we have to increase the flow rate through the filter (preferably a larger filter).

Last Updated on Friday, 31 October 2008 14:29


Is There a Lighter Side to Koi Keeping?


There seems to be only one side to koi keeping - a serious side. The days of fun and humour in the hobby seem to have escaped us. Therefore, I would also like to add to the situation - the HEAVY side of koi keeping or HSOKK for short. We should never take our hobby too lightly. There is a very serious side to koi keeping - long unpronounceable Japanese names, blood lines, future potential and the often used "oh no, no what have you done" look when you describe your filter system to some one who has other ideas. Slapping of the forehead or placing the hands over the mouth or raising the eyebrows whilst whistling between the teeth often accompanies the “ONNWHYD”  - oh,no,no what have you done - look. False teeth can be detected by a gentle rattling that accompanies the whistle. Cavities in the teeth create a melodious soft echo reminiscent of a dolphin’s mating call.

Last Updated on Thursday, 18 November 2010 22:00


Koi Nutrition


About 8 - 10 years ago I really battled to get good growth out of my koi collection. The reason? - The high cost
of koi food. This statement is not pointing finger or sarcasm, but it is an inescapable fact. If you have a large number of koi and you feed them well, it will cost a lot of money. But you will get growth.

Last Updated on Thursday, 16 April 2009 21:37


Koi Pond Stocking Densities

In our wonderful hobby – koi keeping – we all tend to fall into a deadly trap, the trap of over stocking our ponds. Koi keepers often keep every koi they buy for as long as possible. Often the quality deteriorates but we still keep them and they keep on growing.

One of the fundamental principles of good koi keeping is good water quality. Look after the water and the water will look after your koi. As we add koi so the pond environment deteriorates as koi are continually feeding and growing. This in turn means that the oxygen is continually extracted from the water and toxic ammonia is added. Consequently the number of koi that can be safely kept in a koi pond (given volume of water) is limited.

It is very important to keep this in mind - each koi needs a minimum amount of water to live a healthy life and grow to its full potential.

Water has a limited koi carrying capacity. The oxygen that is dissolved into pond water being one of the main considerations for life is limited. Further as koi excrete toxic ammonia directly into the water there are limits as to the amount of ammonia koi can tolerate in a given volume of water – even with filtration.

Last Updated on Tuesday, 24 November 2015 13:12



The addition of montmorillonite clays to fish ponds have proven benefits. Many koi keepers used these clays with great success. Montmorillonite clays are commercially available under various brand names depending on the country of origin.

Montmorillonite clays, vary in chemical composition and purity, enhance water quality, replenish and augment minerals and remove certain unwanted wastes. The uses and benefits go further than this. Montmorillonite improves the lustre and skin quality of koi as well as heightening the colour. Added to food it is claimed to aid digestion and increase the koi’s ability to assimilate the vitamins and minerals required in their diet.

Some claims are made that organic waste such as DOC will be removed from the pond. The ionic exchange capacity is increased. Some koi keepers use very high dosages to remove suspended algae.

There are several forms of brand names of montmorillonite available on the market. Some products are a pure montmorillonite clay. Others are a less pure form and have to be processed to remove and eliminate impurities they are mined with. Some brands claim to have bacteria additives. Other may have additives to the clay such as extra minerals, above what is naturally found in the clay. Whilst others are a montmorillonite clay / zeolite powder formulation.

Last Updated on Friday, 31 October 2008 12:14


Pond Depth

First published in 1996 – updated 2006

This essay was written in response to enquiries that were received after publication of the article recalling my personal experiences on koi nutrition in KOISA # 75.

Society members queried the statements that were made on depth and growth. Thank you for the interest and response. In particular, members asked about the statement - "It may come as a surprise to some collectors, but I have never considered depth to be critical in achieving growth." KOISA readers have asked me to elaborate on this statement.

One of the claims made in koi literature and by some South Africans are that ponds have to be deep to achieve good growth in koi. Further claims were and are regularly still made that koi keepers cannot grow koi to a large size in a shallow pond. Please note the two words that have been highlighted.

Last Updated on Friday, 31 October 2008 11:52


Pond Depth - A Sequel

Browsing through the wonderful book - Nishikigoi and Ponds, published by the ZNA - I discovered information that may be of interest to society members.

Each pond has a picture of the owner as well as a picture of a chosen koi (possibly the owners favourite koi) and specifications on the ponds. These books are collectors items. The print quality is outstanding as is the quality of the paper and binding.

There were just over 150 Japanese ponds catalogued. Many of the top collectors of koi in Japan have their pictures and ponds are listed. A few mud ponds were displayed as owners ponds but these were from known breeders.

Last Updated on Friday, 31 October 2008 11:57


Pond Side Identification

A field guide to Koi varieties to assist judges & enthusiasts in the identification of Koi. Based on the Idea and Concept of Sarel van Rensburg.

Please click here to download the Pond Side Identification chart

Last Updated on Friday, 30 January 2009 10:04

The Immune System of Koi - Further Studies

I submitted this article some years ago to KOISA. There is much valuable information for new members of the Society so I request the editors to re-publish this fascinating essay.

Although the following essay demonstrates the effect of hormones on the immune system, other hormones can have an effect on the growth of koi. If a koi does not grow in your collection, experiment by removing it to another pond, if possible. If it starts to grow then you know that the hormones from the other fish were affecting the growth of that particular fish. If it does not grow then one of two things has happened - the genetics of the fish has dictated the size of the fish or the fish is older than you know or realise. Just as in all creatures, growth hormones stop after a certain age and the creature stops growing (unless you are a body builder and munch on your daily hormone). (does that sound right?).

A study by Perimutter, Alfred, Daniel Sarot, Man-Lin Yu, Rocco Filazzoia and Seely on the Effects of Crowding on the Immune Response of Fish indicates that there are "other" hidden factors at work than first meet the eye.

These are not readily visible or apparent to most koi keepers. Sometimes we simply notice that our koi die without explanation. Perhaps the study by Perimutter et al can throw some light on this phenomena.
Their study may indicate that fish kept in overcrowded conditions suffer impaired immune systems as a result of biochemical agents released into the water by the other fish living in the pond.

Last Updated on Friday, 31 October 2008 12:15


Use and Abuse of High Rate Sand Filters for the 21st Century Koi Keeper

There are only two types of koi pond filters. They can be classified as pressurised and non-pressurised. One of pressurised filters used on koi ponds are the sand filters adapted from swimming pools . As time marches relentlessly into the 21st century we review an enigma from the murky world of koi pond filters – the sand filter. This dreaded, misunderstood piece of equipment is still despised by some but utilised successfully by many.

In the 80’s koi keepers were experimenting with different filter systems and it was discovered that the freely available, pressurised swimming pool sand filter made a very good mechanical filter for a koi pond. Sand filters were freely available and easy to install. It was also discovered that as this apparatus worked efficiently the fine sand bed clogged up rapidly and the end result was clear water. The speed of clogging depended on the amount of organic material (both bacterial and algae) produced by the individual pond and the size of the sand granules. In some cases, when fine sand was used, the result was frequent backwashing every second day. Chemically treated water in swimming pools does not produce this rapid clogging as the chemicals kill the bacteria and algae. But we are dealing with life in our ponds and we have to adapt accordingly.

Last Updated on Friday, 31 October 2008 14:25


Water Restrictions and Koi Keeping

Although we are in a drought situation our climate in South Africa has been variable over many years. We have periods of drought and periods of good rains. Do you remember 5 years ago the amount of rain we received? I recall my driveway collapsing where the ground was water logged and the bricks just sunk into the ground. Remember 10 years ago – well the spruit near us was a raging torrent. My koi pond overflowed like a water fall. I had to build diversions at the back of the property to guide rain water way from the pond area that ran into the property from the house next to me. Ponds on the West Rand had so much rainfall that the pH of large ponds was altered significantly. The rain was falling at a low pH of 4.5.
In South Africa we have entered a phase of drought and water restrictions. So what do koi keepers do? We can’t put our heads in the ground and ignore the current situation.

Last Updated on Wednesday, 02 November 2016 20:44


Water Temperature and Koi

Temperature is one of the critical factors directly influencing every aspect of our koi and pond life. Temperature has a direct bearing on metabolic rates of living organisms in the pond. It has a direct bearing on the health and growth of koi, oxygen levels in the water as well as the oxygen consumption.

There are however, upper and lower limits to what can be considered good or ideal water temperatures. As temperatures rise so does the rate of growth of our koi. Up to a certain point this is true, but beyond a certain point as temperatures rise, the oxygen saturation levels of water declines. At about 28°C there is no further point in trying to achieve higher water temperature as the amount of oxygen that can be dissolved in the water becomes the limiting factor in conversion of food to growth.

On the other end of the scale below 10°C metabolism is reduced to the point where the body is hardly functioning. Below 5°C koi go into hibernation. And at around 2°C for any length of time the fish are close to death.

Last Updated on Friday, 31 October 2008 14:28