SF Bay Area Koi Club

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  • 02/03/2018 7:52 PM | Anonymous member (Administrator)

    More than three-quarters of the earth's atmosphere consists of nitrogen, yet only four-hundredths of one percent of the mass of the oceans, atmosphere, and earth's crust is composed of nitrogen.

    Although nitrogen is not a major component of oceans and land masses, it is an essential element for the formation of proteins in both plants and animals. Rainwater does the critical job of transferring nitrogen from the sky to the soil.

    The Chemistry of Nitrogen

    Nitrogen gas is a very stable two-atom molecule that doesn't easily interact with other atoms or molecules. For example, although three-quarters of every breath you take consists of nitrogen, none of that is metabolized by your body. The same is true of nearly all plants -- they can't take nitrogen directly from the atmosphere. In fact, legumes that can take nitrogen from the atmosphere don't do it directly, but through a symbiotic relationship with "nitrogen-fixing" bacteria in their roots. The bacteria "breathe" in nitrogen and convert it to compounds that the roots can absorb.

    Nitrogen and Water

    Nitrogen's chemical stability means puree nitrogen doesn't mix very well with water. But nitrogen compounds, such as ammonium and nitrates, do mix with water. If those nitrogen compounds exist in the air, they can mix with water and come down with rainwater. The question then is, how can stable nitrogen molecules convert to nitrogen compounds? The answer is that it takes energy. For example, lightning provides enough energy to split nitrogen molecules and stimulate the formation of nitrates -- molecules with nitrogen and oxygen molecules. Bacteria decomposing animal manure and internal combustion engines are also sources of energy that produce nitrogen compounds that can end up in the atmosphere.

    Nitrogen in Rainwater

    A 2004 study of the chemical composition of rainwater at 48 sites in 31 states found nitrates in nearly all the samples, although there was a high degree of variation in both time and space. Several studies in the 1990s showed that locations along the coast of the Gulf of Mexico could expect to get 18 pounds of ammonium and nitrates per acre per year from rainwater. That's about a tenth of typical nitrogen requirements for growing crops.

    The Good and the Bad

    Because rainwater contains nitrogen in forms that plants can absorb, and plants need nitrogen to grow, farmers have noticed that rainwater stimulates more plant growth than water from other sources. That's good, in that farmers don't need to apply as much artificial fertilizer. However, in some cases human activities result in an excess of nitrogen in rainwater. That has the effect of throwing off the balance in some fragile ecosystems where some plants -- typically algae -- that are normally limited by a lack of nitrogen now have enough extra nitrogen from rainwater to choke out other organisms.


        University of Wisconsin: The Elements
        Carleton College: Rainwater Chemistry Across the United States
        Highlights of Agricultural Research: Free Nitrogen from the Sky?
        Wisconsin Technical College System: Plants Prefer Rainwater
        National Atmospheric Deposition Program: Nitrogen in the Nation's Rain

  • 01/22/2018 9:05 AM | Anonymous member (Administrator)

    Koi whiskers are known as maxillary barbels.

    They are slender, whisker-like organs covered with taste buds and olfactory sensors (nose) to help them smell food. This is especially true as Koi ancestors, common carp, were scavengers and foraged in murky water and muddy pond bottoms. This sense allows them to taste food before ingesting it. Koi have one set of barbels on each side of the mouth, located on the upper lip, for a total of four barbels. Barbels are a distinct feature to distinguish Koi from goldfish, which do not have barbels. Barbels can be seen on young fry if you look closely. There are a few other species that also have barbels, including Goatfish, Hagfish, Sturgeon and Zebrafish. 

  • 12/20/2017 6:57 AM | Anonymous member (Administrator)

    We are constantly reminded not to feed our Koi too much - both for the sake of Water Quality, and for the health of the Koi.  And this time of year, some of us are not feeding at all because the water temperature is blow 50 degrees.  But is it possible to feed the Koi too little?

    First, we know that Koi food should be high protein year-round.  It was previously thought that Koi benefit from feeding a lower protein level in the cooler waters of spring and fall, but now it is agreed that we should feed a single, high-protein feed year-round, and vary the quantity based on water temperature.  Another thing we know is that Koi growth rates increased by 60% when they were fed 3 times a day verses once a day.  Remember that Koi are grazers, and benefit from more frequent and smaller meals.  So take the quantity you are planning to feed for the day, and split it up between the feedings.

    For other fish, it is recommended to feed them 0.5-2.0% of their body weight.  For Koi, it is suggested to feed between 1-3% of their body weight. 

    But does that work?  The weights of Koi vary drastically even if they are the same length, and most of us do not weigh our Koi regularly.  And it is not possible to limit the amount eaten by any single Koi when they are fed in a group.  If a group of Koi appear to be "thin," they might benefit from increasing the amount fed at each feeding.  If a single Koi appears thin, it could be genetics, or a health problem, or simply a less aggressive Koi that doesn't enjoy the melee that occurs during feeding.  Most hermaphrodite Koi remain very thin, and sometimes sickly, throughout their lives.

  • 12/07/2017 1:22 PM | Anonymous member (Administrator)

    Ah - the dreaded yellowish looking head...  One of our K.O.I. nutrition students recently asked why some Koi have yellowish skin, rather than pure white.  Here are some of my thoughts about yellowish skin...

    The quality of Koi food DOES matter!  For years, I used cheaper food, and was quite happy with the results.  My Koi never looked perfect, but I just chalked it up to poorer genetics...  Then I started some experimentation with different foods.  I don't currently have any show Koi, so figured I should learn as much as possible with the Koi I have...

    My first experiments started when I was building my monster pond.  I had 12 Koi in a show tank in the basement for 3 years.  I fed them different foods for 6 months at a time, and noted the results.  I discovered that the effects of foods vary considerably!  Koi develop different body shapes, the food affects color, and there is certainly a difference in the amount of waste the Koi produce (poop) depending on the food!  In the 3 years, I put on over 12" of growth on each Koi in less than 400 gallons of water - they grew from about 14" to 26-30"!  That's a LOT of fish in very little water!  I did it with 50% water changes, and blasting the bead filter with 120 psi air for 5 minutes a day.  I learned that biobugs are not easily affected by filter cleaning, and that ShoKoi produced the least waste of any of the foods!  None of the Koi had good whites - and I was told that was because of lack of sunlight - I just had a grow-light over the tank...  Now, I think it had more to do with the food, and the fact that they didn't spawn in the tank...

    Once I got the monster pond up and running, I bought some small Koi, and played with different foods to test growth rates.  The standard food used by most high-end Koi keepers is Saki Hikari.  Every other food is compared to that.  I tried a high end food provided by a breeder - and the Koi didn't like it, plus it was super-oily and did horrible things to my water quality!  I tried Purina Koi feed (Mazuri) - and the Koi had poor body shape and didn't grow properly.  Saki Hikari was OK - sorta middle of the road.  They Koi ate it, and they grew, and they looked OK.  Then this year, I tried a new food just imported in the USA.  Called JPD Shori - there is a another blog article about that food.  Turns out that JPD is the largest producer of Koi food in Japan!  Shori is their premium food.  WOW - huge difference!  The Koi loved it - they now wait in the feeding area an hour before each feeding!  And suddenly, these middle-of-the-road Koi looked AWESOME - you can't believe the difference in the whites - instead of slightly yellow - they were fluorescent white!  Which of course makes all the other colors just shine!  The reds look more intense, the blacks look blacker - even the yellows had more intensity of the pigment.  Go figure!  You never could have convinced me that one factor - food - could make THAT much difference - but it did!  Of course, it could be some combination of my water quality and the food.  Maybe Shori only works with my water quality?  Some of the high-end Koi keepers in my area are going to test it next year, and then we'll know if it's a one-time phenomena, or if it's something that's repeatable in different circumstances.

    As you know, there are LOTS of other things that affect the quality of the white.  The biggest is Nitrates.  If you can keep Nitrates down below 5ppm, then any yellowing of the skin is coming from another problem.  Koi that have been sick, and have compromised liver or kidneys become yellow.  Color foods generally make whites look pink in my experience.  I associate yellows mostly with poor genetics.  When young Koi become mature, and they spawn for the first time, I always find they look better the following year after the spawn.  The eggs and sperm seem to collect unwanted pigment from the rest of the Koi, and once the Koi has spawned, the Koi is left much whiter.  Egg-bound females are almost always yellowish... Water changes seem to have the biggest affect on whites - because of the nitrate reduction.  Plants also reduce nitrates - but somehow, Koi in plant ponds never look as good as those in ponds with massive water changes...  Koi in mud ponds with green water usually have awesome colors - especially red - from all the algae.  Whites can look awesome in mud ponds, or not - I suspect it depends on the water chemistry.  And last, stress really affects how Koi appear...  Some fish stress when you look at them!  LOL  Some have compromised genetics so their organs never grow properly, and they die before they are 6 - meanwhile their whites appear yellow.

    So, if your Koi appear yellowish - go down the list of likely suspects.  Switch to a premium Koi food.  Check nitrates.  If you have anything over 5 ppm Nitrates - do a LOT more water changes...  Did your Koi spawn this year?  If you can check all these boxes, then I'd guess it's just genetics.  You really do have to look at bloodlines when you buy - but the great news is that there are now tons of really good bloodlines, and you can get $30 Koi that have fluorescent white - although they all have plenty of other problems that prevent them from being show fish... 

    I guess that's why this hobby is still so fascinating after 30 years!  There's always something new to learn, and the Koi are incredible teachers!  Experiment with your pond and have FUN leraning!  To me, that's what Koi keeping should be all about!

  • 11/24/2017 8:14 AM | Anonymous member (Administrator)

    1.  Koi originate from Japan and represent love and friendship in Japanese culture.

    2.  Owners who received their Koi as a gift are believed to have good luck.

    3.  In Japan, Koi are often passed down from generation to generation, as a family heirloom.

  • 11/15/2017 7:43 AM | Anonymous member (Administrator)

    Did you know the legend of the waterfall, where a single Koi was rewarded for its perseverance and determination and turned into a dragon?

    One particular legend is the Koi fish’s claim to fame. An ancient tale tells of a huge school of golden Koi swimming upstream the Yellow River in China. Gaining strength by fighting against the current, the school glimmered as they swam together through the river. When they reached a waterfall at the end of the river, many of the Koi turned back, letting the flow of the river carry them away.

    The remaining Koi refused to give up. Leaping from the depths of the river, they attempted to reach the top of the waterfall to no avail. Their efforts caught the attention of local demons, who mocked their efforts and heightened the waterfall out of malice. After a hundred years of jumping, one Koi finally reached the top of the waterfall. The gods recognized the Koi for its perseverance and determination and turned it into a golden dragon, the image of power and strength.

    Symbolism and Meaning

    Koi fish are associated with positive imagery. Because of the dragon legend, they are known as symbols of strength and perseverance, as seen in their determinative struggle upstream. And because of the lone Koi that made it to the top of the waterfall, they are also known as symbols of a destiny fulfilled. Resulting from its bravery in swimming upstream, the Koi is oftentimes associated with Samurai Warriors in Japan. The integrity and high sense of character Koi are known for makes them a popular tattoo choice both in Asia as well as America.

    The Koi is known for its strength, individuality, character, and perseverance.

    Koi fish are also symbolized according to their coloration. Black Koi represent masculinity. It also signifies a patriarchal role. Gold Koi symbolize prosperity and wellbeing in business. Blue Koi, often associated with the role of the son, represents tranquility. Red Koi represent strength and power. It also is recognized as the matriarchal Koi.

    Whatever the legend or color, Koi fish will always carry a positive weight. Whether it be good fortune, longevity, perseverance, or courage, the Koi fish encompasses it all.

  • 11/07/2017 7:04 AM | Anonymous member (Administrator)


    While we may have control over the amount of water we put into our ponds, we don't have control of what's IN that water.  Turns out that many water supplies have been inundated with chemicals from sewage treatment plants.  Wells are also a problem, as chemicals leach into ground water supplies.  This article is about a study that concluded that 1/5th of male fish were transgender or hermaphrodites. A fifth of male fish are now transgender because of chemicals from the contraceptive pill being flushed down household drains, a study by Professor Charles Tyler, of the University of Exeter, has suggested.

    Male river fish are displaying feminised traits and even producing eggs, the study found. Some have reduced sperm quality and display less aggressive and competitive behaviour, which makes them less likely to breed successfully.  The chemicals causing these effects include ingredients in the contraceptive pill, by-products of cleaning agents, plastics and cosmetics, according to the findings. "Many other chemicals that are discharged through sewage treatment works can affect fish, including antidepressant drugs that reduce the natural shyness of some fish species"  says Professor Charles Tyler.

    Professor Tyler presented his findings in a key-note lecture at a symposium where he explained that the offspring of such "transgender" or "intersex" fish can also be more sensitive to the effects of these chemicals in subsequent exposures. Tyler said: "We are showing that some of these chemicals can have much wider health effects on fish that we expected.  "Using specially created transgenic fish that allow us to see responses to these chemicals in the bodies of fish in real time, for example, we have shown that oestrogens found in some plastics affect the valves in the heart." Tests showed 20 per cent of male freshwater fish, such as roach, at 50 sites had feminine characteristics.

    More than 200 chemicals from sewage plants have been identified with oestrogen-like effects and drugs such as antidepressants are also altering fish's natural behaviour, his study found.  Professor Tyler said, "Other research has shown that many other chemicals that are discharged through sewage treatment works can affect fish, including antidepressant drugs that reduce the natural shyness of some fish species, including the way they react to predators,"  Professor Tyler will presented his findings in the opening lecture of the 50th Anniversary Symposium of the Fisheries Society in the British Isles at Exeter University this last July 2017.

    Dr Steve Simpson, who organised the symposium, said the week of talks would gave "fish biologists from around the world a chance to exchange ideas and discuss how to protect dwindling fish populations in rapidly changing seas and rivers, before it is too late.”  Other research discussed at the event includes how the destruction of coral reefs and their distinctive sounds means fish are getting lost in the water, how fish are shrinking because of climate change and how power cables can disrupt how fish find sexual partners.

    From: www.Telegraph.co.uk (link is external) by Sophie Jameson, July 2, 2017

  • 10/26/2017 8:52 AM | Anonymous member (Administrator)


    Santa Clara Valley Koi and Water Garden Club was called in to assist  FEMA / ASPCA  with Koi rescue for the Sonoma Fire victim's koi ponds October 22nd.  We responded . Over 150 Koi have been rescued from these wildfires so far.

    Members donated time and resources to assist by setting up temporary holding tanks and providing equipment and supplies to care the rescued Koi from fire damaged homes and properties that have been brought in by animal services. Some of the most injured Koi have been taken to UC Davis for treatment. 

    Many of the Koi fire victims are being temporarily housed and cared for until they can be returned to their owners or, if needed, adopted in the coming weeks.  As the areas are opened up for residents to return home more Koi are anticipated to be moved to our temporary holding tank facility at the Sonoma Animal Shelter.

    Thank you to our membership,  sponsors, and friends for for caring for these aquatic fire victims in their time of need!   Bless those Koi that didn't make it. 

    If you would like to help support these efforts please send donations to:

    SCVKWG, PO Box 54368, San Jose, CA 95154 

    Please note that your donation is for the Sonoma / Santa Rosa Fire Koi Rescue Project. Donations are tax-deductible.


    Sent by:

     Eve Bretzke

     Webmaster / Newsletter / Membership

    Santa Clara Valley Koi and Water Garden Club

     Email:  info@sckoi.com

     Website: www.sckoi.com

  • 10/19/2017 7:16 PM | Anonymous member (Administrator)

    As of September 2017, this is the latest and greatest article available anywhere on KHV. This article was published by the University of Florida Extension Service, and written by Kathleen Hartman, Roy Yanong, Deborah Pouder, Denise Petty, Ruth Francis-Floyd, Allen Riggs and Thomas Waltzek.

    It covers the history of KHV, exactly what KHV is, the signs of KHV, how fish get infected, how water temperature affects KHV, how to know if your Koi have KHV, KHV treatments, KHV prevention, how KHV differs from other viral diseases, how humans are affected by KHV, regulatory concerns and whom to contact for more information.  8 pages.  There is also a comparison chart for KHV, SVC and Carp Pox so you can learn to tell the difference.

    CLICK HERE to download your copy!

  • 10/10/2017 1:00 PM | Anonymous member (Administrator)

    This is a great article about a plant that should be used more frequently in planted ponds and tub gardens!

    Sometimes you just need to loaf…  I was wandering around my computer, doing random searches. I went to my default setting and looked for aquarium related plants.  I wasn’t really looking for find anything, but more to see what was available.  I surfed through the listings, and came across one with a bunch of plants I hadn’t seen before. 

    I pulled out my trusty Aquarium Plants by Christel Kasselmann, and was able to Identify all the plants listed but one.  So I turned to the internet, and I found it!

    Hygroryza aristata was first described way back in 1789 as Pharus aristatus.  The plant is actually native to Southeast Asia, specifically India, Sri Lanka, Pakistan and China.  But what surprised me about this plant is that it is actually a species of grass.  In fact, it is the only species of grass that can be kept in either a pond or aquarium.  Of the over 10,000 species of grass (including both domesticated and wild species) only one, Hygroryza aristata is suitable for aquatic usage.

    It is a monospecific (a genus with only one species) floating species, with a central stem from with leaves branch approximately every 1.5 cm (.5”) to every 10cm (4”) depending on growth conditions.  Each branch, which alternates from one side of the main stem to the other, consists of an inflated leaf sheath and then the leaf itself.

    The leaf sheath (described by one source on the internet as “water wings for the rest of the plant”) is a tubular section approximately 10 cm (4”) in length and 1.5 cm (.5”) in circumference.  As inferred, this leaf sheath enables the plant to float.

    The leaf is about the same length as the leaf sheath but about double the width at the maximum spread, is elliptical in shape, and can range in colour from a light through dark green shade and in optimum growth conditions will show a purplish tint.  It will either float on the water or will grow emergent above the water.

    The roots, similar to those of water lettuce (Pistia stratiotes), are long and feathery, resulting in an excellent hiding place for fry and shy fish.  The roots descend from each branching of a leaf portion from the main stem.

    In nature, the plant can form dense floating mats in both lakes and slow moving streams.  As mentioned, it is native to Southeast Asia and has been used as a forage source for cattle, but it has also become a weed species in rice paddies.  There is some concern that it may become an invasive species in the southern United States.

    Aquatic hobbyist usage can be both for open top aquariums and ponds.  It apparently required high to very high lighting, and is reputed to be a nutrient hog.  If sufficient nutrients are not present, there may be yellowing of the leaves.  As such, it is recommended that good fertilization of the aquatic environment occur.  But if care requirements are met, it will grow very fast and require pruning to prevent if overshadowing other plants beneath.

    Propagation is by stem fragments (that means that you can probably break the stem, and each piece will result in a new plant) or occasionally by seed.

    The genus name is derived from Hygro, the Greek word for moisture or wet, and from Oryza, the genus name for some types of grass.  The species name, Aristata, is from the Latin word for “bearded.”  Hence it is a “water grass that is bearded.”

    This is a plant worth seeking out in larger pond supply locations, because it is so suitable for use in goldfish ponds and outside tub gardens.


    From: Tank Talk, March 2013, Volume 40, Number 07, Durham Regional Aquarium Society, by member Derek P.S. Tustin

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