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  • 01/23/2019 9:36 AM | Anonymous member (Administrator)

    Recently the question was asked about how much does a Koi weigh that is a certain length? Here are some thoughts, and a few charts...

    I've never raised koi fry but I've been a fish geek most of my life and I know plenty of other who also fall into this category. Here's what I can tell you from my experience and the experience of others.

    Fish grow most (fastest) when they are young. If they are to reach their full genetic potential, they need to be grown fast when they are young.

    Young, fast-growing fish need higher protein food than older fish. Stunting a fish with retarded growth when they are young cannot be compensated for later in the fish's life. Feeding heavy and often promotes fast growth. However, you need be careful to keep good water quality as good water is essential to good health and fast growth. This can be tricky as you need to offer enough food to keep them growing but not pollute the water.

    I know a guy who used to raise angelfish. He changed nearly 100% of the water in every tank every day. People who raise discus are also water change fanatics. Changing water relates to ridding it of growth-retarding hormones.

    There are some charts which I copied off the internet, and I'll provide below - but note that the VBGF is for farmed Koi - and that most ornamental fish in home ponds GREATLY exceed the weight at which those fish would be harvested for food... Unfortunately, that means that there is not a very good correlation between size and weight for Koi - we certainly see skinny Koi and Koi that can weight twice as much and be exact same length... And the same can be said for length vs. age - it varies considerably, based on many factors, including genetics and water quality, type of food, etc.

  • 11/18/2018 4:22 PM | Anonymous member (Administrator)

    Dr Paula Reynolds describes it very eloquently, in Koi-Carp Magazine, August 2000.  "The outermost body protection for koi is the mucus coating which forms a layer known as the cuticle. 

    The mucus is comprised of natural secretions containing antibiotics, which are the proteins that fight disease. Primarily the mucus prevents the adherence to the body by pathogens such as bacteria, virus and parasites. These antibiotics produce a general response to all the harmful organisms in an aquatic environment rather than targeting one harmful organism specifically."

    The enzyme lysozyme and other secretions termed bacteriolysins, are also found throughout the mucus layer, defending the fish when under attack by diseases.  Complement is the term applied to the system of interlinks enzyme reactions that take place in the mucus layer and also in serum. The mucus layer also contains unwanted matter from skin cells which some body parasites use as a source of nutrition.  It is from this layer that the very small amount of mucus is removed to be viewed microscopically when a parasite problem is suspected.

    The consistency of the mucus layer can be changed by diseases. When nitrite is in the water the koi can take on a soapy appearance as this substance interferes with normal mucus production. In other cases the mucus becomes thicker or even watery or can be shed altogether as it mounts a variable response to health problems. A koi striped of its mucus coating becomes more vulnerable and that is why chemicals that removes it, such as formalin has to be used cautiously.

    By: Chris Neaves

  • 11/01/2018 10:56 AM | Anonymous member (Administrator)

    If you've missed the previous posts, then you may not know that the Ausies are planning to release KHV in the Murry-Darling basin in Australia to control unwanted carp.  Here is another excellent article that voices serious concerns over the government controlled planned release of KHV.

    The extermination will begin within years - an especially virulent strain of herpes virus will be gradually introduced to rivers, and the disease will rampage through the carp population, killing as much as 95 per cent.

    Carp - also known as 'blubber lips' and 'mud sucker' - are those pale-gold, pale-silver creatures that can grow to monstrous size in rivers and creeks.

    More than 100 years after being introduced into Australia by recreational anglers and do-gooder "acclimatisation societies", it's been decided the carp are causing too much damage, churning up the river bottoms and causing a nuisance, and and they have to go. Essentially Australia is looking to deploy a biological weapon against a bunch of fish.

    Their mass extermination is being called "carpageddon".

    This is not the first time we've deployed what's called "biological controls". Maybe the most notorious is the cane toad, which was introduced to control the cane beetle, and ended up ignoring the beetle and driving native species to the edge of extinction.

    Then there was myxomatosis - introduced in the 1950s, it successfully killed lots of rabbits in Australia. Unfortunately, it then spread overseas, out of control, and killed almost all of the wild rabbits in France and the United Kingdom. The lesson: Using viruses as "biological controls" is playing with fire.

    What could possibly go wrong?

    Though the plan has been around for a decade, the idea of giving carp herpes only truly captured the public's attention last year, when the Deputy Prime Minister announced $15 million funding.

    Barnaby Joyce - who threatened to euthanize Johnny Depp's dogs over non-compliance with biosecurity laws - delighted in talking up the plan during question time, things got a bit weird. "We are afflicted in this nation with these disgusting mud-sucking creatures, bottom dwelling mud-sucking creatures," Mr Joyce said, staring at the Opposition benches. "We on the Coalition are going to make sure we have a healthy river and a healthy economy because we're going to get rid of the carp."

    But not everyone is as gung-ho as the Member for New England.

    Hack has spoken with a pet management professor, a carp-fishing tycoon, and a specialist fish veterinarian who doubt government can control the outbreak of the virus and handle the scale of carpageddon.  By declaring war on the freshwater pest, they say, Australia may drown under a sea of herpes-disfigured carcasses.

    How many carp are we talking about?

    Exactly how many carp are in Australian waterways is not known with any accuracy - estimates range from two to six million tonnes. Let's say there's four million tonnes, that's the equivalent of 100 fully grown humpback whales, or 25,000 bottlenose dolphins.

    It's true that we've handled feral animal mass exterminations before.

    The most recent was in the mid 1990s - a strain of calicivirus imported from Czechoslovakia jumped quarantine and killed 10 million rabbits within eight weeks.

    "The Murray River area stank of dead carcasses because it went through so quickly and killed 80 per cent of rabbits," says Dr Braysher, a University of Canberra professor and recognised expert on the topic of feral animal management. "And that's on land - imagine concentrated in a water system."  In the case of calicivirus, the rabbits were left to rot. This isn't an option with carp. "They're going to need lots of people there to collect dead fish because once they die those fish will come to surface and start rotting," says Dr Braysher.  As they rot they'll take oxygen form the water. As that happens all other aquatic wildlife that depend on oxygen in the water will die."

    "If they don't get dead fish out of water it will have major effects."

    Apart from suffocating the other fish, including native species like Murray Cod, the release of phosphorous and nitrogen will promote blooms of toxic algae.  "If you think we have blue green algae blooms now, think about when we have massive fish deaths," says Keith Bell, probably Australia's most experienced carp fishermen.

    Apart from killing more fish, and stopping people swimming, the algae could poison the water supply of small towns."Lots of little towns still draw water from rivers," says Keith. "Their filtering system can cope with fish, but not once the fish die and become toxic."  OK, just scoop them out.  This is only possible if the outbreak of the virus is carefully controlled. If authorities lose control, and too many fish die at once, there won't be enough people to scoop them out. Controlling a virus is very difficult - so difficult Dr Braysher thinks its impossible.  "I don't think they can," he says.

    The carp herpes virus, like all viruses, spreads at an exponential rate.

    In 1-3 days of its release, the dead carp will begin floating to the surface with bleeding gills, sunken eyes and pale patches on the skin. They suffocate over about 48 hours. The survivors, horribly disfigured, will swim about infecting other fish.  Rapid response crews will travel around the countryside netting the dead fish and dumping them in trucks for landfill.

    The virus will spread through New South Wales, Victoria, and South Australia - in the Murray-Darling Basin, the catchment for Australia's largest river system, it's estimated carp are 90 per cent of the fish biomass.  According to Dr Richmond Loh, a fish veterinarian with a particular interest in koi, a species of carp, the virus spreads easily.  It can survive in water droplets on a bird's legs,  This means it could be hard to contain. Flying upstream, the bird could transport the virus hundreds of kilometres.  A single drop of viral water in Lake Burley Griffin, the big man-made lake at the centre of Canberra, right next to Parliament House, could send belly-up an estimated 10,000 tonnes of carp in a single sitting week.

    "Once the virus is out there there's no going back," Dr Loh says.

    The virus once hit one of the major recreational lakes in the US and you couldn't go water skiing because you had to dodge all these floating fish everywhere.  "The place stunk really badly."

    Even without birds couriering the virus about, it could still be spread deliberately by humans. It happened with calicivirus - some New Zealand farmers reportedly smuggled it into their own country, to kill the rabbits in their paddocks.  "The major problem I see is people who will start picking up fish with the virus and transport them upstream," says Dr Braysher.

    We can turn them into pet food or make fish fertiliser  Maybe not.

    Last year, when everyone was learning about the carp herpes plan, there was excitement around the idea that the fish could be turned into pet food or fertiliser.  There's already a company that turns carp into fertiliser - Charlie Carp - and the owner said the company could even expand production to take advantage of the increased supply. Barnaby Joyce proposed the carp could "take the place of horse manure or something".

    It turns out it's not so simple.

    Keith Bell, the fisherman who's responsible for almost all the carp exported from the country in the last two decades, says once the carp begins rotting it can't be used for either pet food or fertiliser. Even if the fish can be collected in time (a matter of hours after they die, he says), the volume would probably overwhelm processing facilities. Carp isn't being used for pet food at the moment, and the fertiliser industry only processes a couple of hundred tonnes per year, according to Keith. "Two to three fishermen keeps Charlie Carp in enough fish for a year," he says. "The domestic human consumption market is 50-60 tonnes a year at a reasonable price.  "It's a wasted resource," says Bell, who was exporting a couple of thousand tonnes of carp per year from Australia from the late 90s until last year, when he sold up and moved to Mississippi.

    "I don't know what the right answer is, but I know this isn't the right answer." Why aren't we exporting more carp, or just eating them?

    The irony is that carp is one of the most farmed fish in the world. In Europe and China, it's considered good eating. Australia is the only carp-culturing country that hasn't had any reported cases of carp herpes. We're deliberately spreading a virus that other countries are desperately getting rid of - the same way we're trying to get rid of carp. The double irony is carp were originally introduced into Australia for human consumption - either released for recreational fishers or raised in fish farms.

    "In fish markets in Sydney or Canberra you can buy carp for $6 a kilo," says Dr Braysher. "People who want them will like them and pay big money for them.  "It's an attitude thing."  Keith Bell says exporting carp from Australia is no longer financially viable.  He says restrictions placed on what equipment he could use to catch the fish - restrictions to minimise the bycatch of native fish - made fishing carp too expensive. There's the bind: by relaxing restrictions to boost carp exports, we'll also be getting rid of native fish.  Keith closed his export business last year. He says he was the last person to export carp from Australia.

    You can't get rid of herpes

    Once the virus is released, it can't be removed. From the moment of the release, expected to be late 2018 or early 2019, there will always be herpes in Australian carp.  There will also always be carp. It's estimated within 10 years the virus-resistant fish will breed up to 60 per cent of the current population.  That means in 10 years time we'll still have a carp problem, and the carp will have a herpes problem.

    Dr Braysher says the carp are here to stay.

    "No established pest in Australia has ever been eradicated," he says.  He says river health and native fish stocks had begun to decline well before carp began to dominate the Murray-Darling river basin in the late 1960s and early 1970s. Getting rid of carp will create a window of opportunity, before they breed back up, to improve river health and native fish stocks to prevent carp once again dominating the system.

    To do this, we have to do more than blame the carp, he says. We have to look more closely at politically-sensitive things like agriculture.  We need to stop cattle getting into the river and destroying vegetation, destabilising banks and churning sediment."  "We all play a part in the degradation of the system, it's not just one individual thing.  "The pest is there taking advantage of a modified system."  "Treating carp is only treating part of the problem."

  • 09/21/2018 2:38 PM | Anonymous member (Administrator)

    By Syd Mitchell

    An interesting question has been asked:  “If an air pump is turned off for an hour in the evening, does the dissolved oxygen in the pond water disappear immediately the air pump stops?”  (The pond has an aerated bottom drain and I assume the air is being turned off so that the Koi can be seen more clearly).

    I could approach the answer from a technical point of view but it is much simpler to draw a comparison with a situation that we all have experienced and can relate to.

    A pond can be compared to a room that has an open window.  Assuming there is no wind to influence the situation, the slow, but steady, air flow through this window will provide adequate ventilation for a small number of people.  As the people in the room breathe in oxygen and breathe out carbon dioxide, the level of oxygen will decrease, and the level of carbon dioxide will increase.  With only a few people in the room, this change will not be noticeable and they will breathe comfortably.  The larger the area of the window, the greater will be the number of people that can occupy the room.

    In comparison with a pond, the open window is equivalent to the surface of the pond.  The greater the surface area, the greater will be the number of fish that can live in it using just the natural gas exchange at the surface to provide them with oxygen and to remove the carbon dioxide that they produce.  In a lightly stocked pond with a large surface area, there will be enough exchange of gasses through the surface area alone and additional aeration will not be needed.

    If you want to increase the number of people that a room can hold, you could blow air into the room by means of a ventilation fan.   This will not only introduce more fresh air into the room, but in doing so, it will also push stale air out of the window and prevent carbon dioxide from building up. The more powerful the fan, the more people will be able to use the room in comfort.  This would be the equivalent of putting air stones into a pond. The faster the air is introduced through these air stones, the faster the oxygen in the water is replaced and the faster the carbon dioxide is removed, so therefore, the greater the number of fish the pond could hold. 

    If you were to turn off the ventilation fan when the room is full, the occupants will not immediately feel the effect but, after a while, as the oxygen is being used up, they will find it harder to breathe.  There will still be some ventilation through the open window, but this may not be enough to prevent the occupants from suffocating.  It all depends on how many people are in the room, as to whether the open window will supply enough fresh air for them to breathe in comfort, or at least survive until the fan is turned back on.  Whether the room is being used for aerobics or for yoga classes, and the number of occupants are factors deciding for how long the ventilation can be turned off. Similarly, in a pond, active fish consume oxygen at a greater rate and also, the more fish there are, the shorter will be the time they can be left without additional aeration.

    If you turn off an air pump for any length of time and don’t want to spend that time doing regular oxygen tests, then watch your fish. They will tell you whether or not they are finding it hard to breathe.  If they are carrying on as normal, everything is fine.  If they start showing greater or more rapid gill movements, or if they spend more time at the surface, they need more air. As a “rule of thumb”, with good aeration and normal stocking rates, there will be a reservoir of dissolved oxygen in the water that will be adequate for them to breathe for an hour or so after the air is turned off.

    A few points you should bear in mind.  The warmer the water, the less oxygen it can hold.

    Saturation values of oxygen in fresh water at sea level (Maximum level of oxygen a pond can hold)

    Koi are happy with an oxygen level of 7 to 8 mg/L (7 to 8 ppm).  They need a minimum oxygen level of 6 mg/L to be comfortable, and they will die quickly if the level falls to around 3 mg/L. So don’t push your luck! As soon as the first fish looks slightly “out of breath”, the oxygen level will be dropping below the lowest acceptable level, so turn the air back on immediately and don’t leave it off for anywhere near as long next time.

    It is a sensible idea, if you feed Koi when the air is off, to bear in mind that as the protein in their food is digested, they produce ammonia. The nitrifying bugs (nitrosomonas and nitrobacter) in the biofilter will soon get busy converting this into nitrite and then into nitrate.  In order to do this, they will use a huge amount of oxygen, which they will also take from the water. Unless there is sufficient continuous aeration in the filters, the water returning to the pond will be depleted of oxygen. As this mixes with the rest of the pond water, it will dramatically shorten the time during which aeration in the pond can be turned off. 

    It is never a good idea to turn off the air supply to the biological chamber of the filter unnecessarily.

  • 09/12/2018 6:46 PM | Anonymous member (Administrator)

    These are some useful tips from Kodama Koi.  Their FL facility was hit by a hurricane last year, and this year, their Hawaii facility was hit, so they have some good advice! Though it's 2018, the huge hurricane hits in 2017 are still fresh in our minds.

    Last year Kodama Koi Garden FL got a lot of damage and suffered from a long power outage.  We are now in 2018's hurricane season.

    Today Kodama Koi Garden FL and I would like to share what you can do to prepare. You will need a:
    • Generator
    • Air pump (highly recommended)
    • Pond net

    Generator and air pump—To save your Koi when a power outage hits, run the generator to power the air pump to oxygenate the water.

    Note: If your air pump is powered by a generator, a water pump and filtration system are not really necessary.

    While the water pump and the filtration are off, please don't feed Koi.  This will help curb ammonia and nitrite levels and water quality deterioration. Koi are fine with no feeding over a week.

    Some people may have only a waterfall or fountain to supply oxygen for their Koi. If a generator is used to keep a water pump and filtration running, that's fine.  But if not, we strongly recommend powering an air pump at least. We believe an air pump needs less electricity than the water pump.

    Also if more electricity is used, more fuel is required to run the generator; and there may be long lines of people waiting to refill fuel in your area.

    Above, Pond cover net—In case heavy rains hit and your pond overflows, the pond cover net will help keep your Koi safe inside the pond.

    A hurricane's potential for damage varies, but we can do our best to minimize it.

    And of course, please keep yourself and family safe, too.

    If you have more questions about prepping your koi for a hurricane, call us in Kodama Koi Garden FL at 954-621-3831.

    Above, Hakko Air Pump 25 LP

    Above, Premium pond cover net - note Koi can't get their fins stuck in this kind of net.

    One supplier is: KodamaKoiSupply.com

    Article Source:  https://mailchi.mp/kodamakoifarm/notice-hurricane-preparation-for-your-k...

  • 07/01/2018 7:06 PM | Anonymous member (Administrator)

    This months blog is from guest writer Katie Michaels <katiem.aqua@gmail.com>

    Image result for koi feeding

    While it might seem quite straight forward, many first-time pond owners worry about what and how much they should be feeding their pond fish, to get the most out of them and to avoid causing pollution problems in the water.

    There is no doubt that feeding pond fish well and appropriately, leads to healthy, bright fish and it’s important to realise that they need different feeding approaches depending on the season, as their needs change depending on the time of year.

    During the summer, it’s warmer and the fish are far more active so they need to be given a high quality protein fish food as their metabolism will be at its peak around now.

    When Autumn arrives, the fish will slow their metabolism as the water temperature drops, so fish require a mixture of protein and wheat-germ based food to accommodate this level of change in their daily activity. During the winter months they will only require wheat-germ based food.

    Then, once the temperatures start to warm up again as Spring arrives, it’s important to switch the diet around, moving from pure wheat germ, back to the combination, and then when summer hits, remove the wheat germ and stick with protein only.

    One of the key things to understand about fish is how to feed them to their optimum level. It shouldn’t be a case of just throwing a load of food in the pond and walking away although sadly this does seem to be a common approach.

    Fish will only eat as much as they want and need and will ignore the rest. If you overfeed your fish then that excess food will stay in the pond lowering the water quality, encouraging algae growth and will lead to discoloured water, bad smells and flies.

    This situation causes pond maintenance issues as filters will get clogged up as will the pumps, causing even more problems for the environment in which your fish are living. It’s really important therefore, to feed fish correctly and efficiently, to avoid the pond turning into a nasty, toxic environment which no-one will enjoy.

    Here are some top tips for feeding pond fish:

            Take your time and observe the fish behaviour. During this time you can watch them and look for any health problems or issues

            Only offer small amounts – wait until the fish have eaten all of it before giving more and stop as soon as they start to lose interest.

            Offer the food to the fish, close to where you are standing so they associate you with food – this helps to create a bond, rather than just throwing the food in any old way.

            Always feed the fish from the same place, so they associate you standing in that area with food to come.

            If you are going away for some time, do not just feed the fish twice as much – they will ignore the food and it will go to waste and rot in the pond.

            Make sure someone else comes to feed your fish if you are going away for any length of time, and instruct them on the feeding rituals and portion sizes.

            Adapt your feeding techniques according to the seasons as fish will require less food in the colder temperatures.

            Make sure you buy higher quality koi food during the summer– don’t use fish tank food for ponds – you can always ask advice from the local pet store or aquarium shop.

            Feeding the fish can become part of a relaxing ritual for yourself as you spend time with the fish and watch them swimming which can be incredibly stress-relieving

            Always keep an eye on the levels of food which you have left to make sure you never run out and leave the fish hungry

            If you have children, get them involved in feeding the fish as a family activity and a way for them to learn how to take responsibility for looking after animals.

            As you spend time with your fish, watch for any changes in their feeding habits (outside of seasonal changes) which might indicate illness or diseases causing problems.

            Make sure the pond isn’t so overgrown with algae and/or pond plants that fish can’t find or see their food.

    Starting a new pond with appropriate feeding habits and routines will result in colourful healthy fish and a pond environment which is pleasant and requires far less maintenance than one which is full of rotting leftover food.

    Feeding pond fish isn’t rocket science so as long as you select the right food, take account of the seasonal changes in fish eating behaviour, and then take your time to feed your fish carefully every day, there is no reason at all why your fish won’t be happy and healthy living in your pond.

  • 05/14/2018 4:01 PM | Anonymous member (Administrator)

    Ever found a predator in your Koi pond?  A woman in Montana got a HUGE surprise!  Luckily, the visitor seemed more interested in eating the vegetation...  


    You gotta watch this video!

  • 05/04/2018 7:44 PM | Anonymous member (Administrator)

    Benefits of Using Nualgi Ponds

    When you supplement your regular maintenance with Nualgi Ponds, you will be able to:

    WATCH YOUR POND FLOURISH – Nualgi Ponds will significantly improve water quality as well as the health of fish and plants. For many eutrophic ponds, results may be visible by afternoon on the first dosem starting with the bubbling up of oxygen, elimination of odor, and Blue Green Algae crashing and floating to the surface.

    SEE MORE– By reducing nuisance algae growth, Nualgi Ponds improves water clarity and visibility to reveal more of the pond’s environment and its inhabitants.

    FEED LESS– By restoring missing nutrients, Nualgi Ponds brings balance to the natural marine food chain from the bottom up by promoting the growth of diatoms and zooplankton – free food for your fish and shrimp!

    SHOW IT OFF– Enjoy peace of mind knowing that your pond is healthy, clear, and odor-free.  Friends and guests will be impressed, and we won’t tell them how easy it was to restore the natural beauty of your pond.

    Nualgi is Safe for Fish, Plants, Amphibians, Birds & Pets!

    garden ponds water lillies

    Mother Nature Approved

    Nualgi Ponds has been tested in hundreds of small bodies of water, and even a few lakes and rivers!  Nualgi Ponds is designed to promote healthy growth and restore balance to the environment by reducing nuisance algae and increasing dissolved oxygen, and has successfully done so in trial ponds since 2005.  

    lake side house

    Yes, I would love to live here.

    No algae? No problem.

    Nualgi Ponds improves the life cycle to significantly increase the health of fish, plants, and critters. By providing essential nutrients on a nano-scale, our patented formula allows nutrients to travel farther than larger, macro-sized particles, reaching every corner of your pond and increasing the bioavailability of the nutrients for easy absorption.

    A bloom of Diatom algae

    The Power of Diatoms

    Within 3 – 5 hours of applying Nualgi Ponds, a bloom of Diatom algae (the good kind!) will develop. The diatom algae bloom out competes nuisance algae for CO2, N, P and other nutrients, causing the bad algae to die off, then locks away some of the nutrients in the new bio mass that is consumed as live food for your fish and zooplankton.

    Nano-silica-based minronutrient.

    Nano-silica-based micronutrient

    Based on 15 Years of Research

    Nualgi Ponds is the fourth generation of patented nano-silica-based micronutrient. Based on 9 years of lab research and 8 years of field research for applications in commercial and municipal water management. The Nualgi Ponds formula specifically helps pond owners improve water quality and manage algae. 

    Nualgi for Koi Ponds

    Here's a link, for quick home delivery.

  • 04/16/2018 7:02 PM | Anonymous member (Administrator)

    Ron has put together a work journal of this pond project.

    Get your copy of Ron's Work Journal Here

    The completed pond is now about 3 months old.

  • 03/08/2018 7:04 AM | Anonymous member (Administrator)

    Water from a household tap, a borehole or well, or rainfall will have unique properties and individual chemistry influenced by the location.

    No two ponds are identical in respect of their water chemistry or biology and many factors will naturally differ. It is not surprising that, the solution to a water chemistry issue that arises in one pond could make matters worse in another. A genuine knowledge of water science requires study at a molecular level, and an understanding of the role of water in Koi physiology and welfare is also needed to be able to offer advice .However, this is not essential for those hobbyists whose goal is simply to provide perfect pond conditions that will support their Koi for life.


    Measuring the pH of pond water tells us the hydrogen ion concentration, a value below 7 is acidic and above 7 is alkaline. Koi are capable of making adjustments internally in order to live in pond water with a pH between 7 and 9 although values over 8.5 may need monitoring to ensure they are stable. The optimum pH for Koi health, growth, and longevity is 7.5 - 8.0. This value is based on research carried out in UK water in my facilities with thousands of Koi for over 30 years. However, ideal conditions may well vary depending on the objective. For example , a Koi keeper may find his water chemistry supports the well-being of his Koi, although it does not preserve the highly prized red colour cells in some of his Koi varieties. Whilst genetics is the major influence, water chemistry has a minor role in colour retention. The pH in a Koi pond must be stable and this means all the changes that occur should be natural and therefore gradual. Water temperature, daylight length, the seasons, as well as the weather can all trigger chemical reactions and Koi have to adapt or they become unwell. Most hobbyists will have seen a Koi in the early morning suddenly dart across the pond surface on one side while adjusting to the new conditions. Some Koi are more sensitive and not all will react in the same way. If a pond with a normally stable pH suddenly alters it will upset the Koi and they may become listless and stop feeding. A more serious impact on their well-being is likely if the pH is in a state of continual fluctuation. If the pH alters, by more than 0.2 most Koi will release stress hormones as they attempt to adjust to the changes and having to adapt for long periods puts their survival at risk if the pH is not quickly stabilised.


    Although KH and pH have to be tested separately to assess how the pH is supported, they are closely associated, as it is by testing KH that the buffering capacity of the pH is revealed. It simplifies water chemistry to state that the pH will always remain stable if the KH level is in excess of 85 - 90 mg/L. At that level, fluctuations are far less likely but we have to keep in mind that pond water is less stable than tap water due to the numerous influences on it, particularly the pond filter system. In ponds, the pH can crash whereas that is not an issue in tap water as it is prepared and monitored by the water suppliers. There are many anomalies in respect of KH as the levels vary around the UK. In some areas, a KH of 1.0 does not always trigger an immediate pH crash. The Koi could remain safe until a pond event takes place such as the introduction of a treatment product. It is possible that as the product goes into solution it will interfere with the delicate knife-edge chemistry that has kept the koi alive until the inevitable crash. Some of the ways in which koi can be protected from a pH fluctuation or crash are listed below. K H buffering with bicarbonate of soda: The KH level of a pond can be raised by adding sodium bicarbonate at 100 gms in 1,000 gallons daily until the level is stable. The drawback with this method is that if there is an unknown reason as to why the pH decreased or crashed , sodium bicarbonate may not hold the level and it will drop yet again. This then adds to the fluctuations the Koi experience and avoiding fluctuations protects the Koi. If daily doses are needed, the Koi keeper can never forget to buffer let alone take a holiday and in such cases, this cannot be seen as an ideal solution. Many buffering products on sale in aquatic outlets are also based on sodium bicarbonate.

    Source: Paula Reynolds, Bsc, PhD,BA - Paula an aquatic patho-biologist, runs Lincolnshire Fish Health Laboratories and Research Centre a company that specialises in research into fish diseases for vets, fish farmers, hobbyists and the aquatic trade in England.

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