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Thread: Comments on reaing koi fry in green water.

  1. #21
    Daihonmei MikeM's Avatar
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    Greg: I defer to those like Dick with real experience raising koi fry. Heres my 2 cents:

    I think the responses you got on the koivet board pretty much cover the likely candidates. If the die-off continues, I do not think you have a choice but to try something like Proform-C. ... Does not sound that you can have confidence in your skills in scoping dead fry remains.

    If it is bacterial, a mild antibiotic like erythromycin may help.

    Next time, when you set up a tank of clean water to age, do it weeks in advance. Set it up in full sun to encourage green water. Consider adding a small amount of aquatic plant fertilizer to encourage unicellular algae. Cover with net to prevent dragonfly larvae or other harmful insect larvae from getting in it. Then when you can add food and fresh water at the same time. In a vat (as opposed to a pond), sponge filters can accomplish your biological filtration if set up long in advance. Do not have to worry about sucking fry into a pump.

  2. #22
    Tategoi
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    Hello Greg

    Sorry to be joining this thread so late. In as much as there may be a bacterial problem, Mother nature always takes a huge number of koi fry
    mostly due to internal defects naked to the eye. I was reading down further in the thread and saw a comment refering to the possiblility of underfeeding. I dont believe this to be the case. The picture that they were refering to (skinny fry) is a classic deformaty found in thousands of fry when they are born and they will all die off eventually no matter how well u care for them. U will also begin to see many young fry with turned out gill plates. This is another classic deformaty as well as tadpole fry, huge heads and a long skinny tail.

    Go ahead and take scrappings. Check for the bad things but remember that between the first and 3rd week ther are many many losses. this is normal, at least it has been in all of my spawnings. Lets hope that this is the case.

    Good luck, Kiefer

  3. #23
    Jumbo gregbickal's Avatar
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    Thanks for the help guys. I lost all but about 15. Next year I will definetly do my water changes with aged well water instead of pond water from my existing pond. Even tho it tested good, it could have contained something.

  4. #24
    Daihonmei MikeM's Avatar
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    That's awful news. I'm hoping one of those 15 proves worthwhile.

  5. #25
    Nisai estanque_koi's Avatar
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    raising fry

    Hello!
    I'm just back from vacations... My fry are doing very well and there are some nice Kohaku among them, some few Sanke also.
    I would like to point out that it is possible to use massive filtration safely right from the start of the breeding process, and this can save a lot of fry in small to moderately sized breeding tanks.
    I have been using a rather massive filtration rate right from the start (before spawning). Due to strong space constraints I was doing all the rearing in a 1250 liters (275 USA gallons) tank. A 5 cm diameter (roughly 2 inches) siphon takes the water from around 3 inches above the bottom of the breeding tank, by gravity, to a 250 liters (55 USA gallons) biofilter. Several sponges attached to the siphon entrance were intended to stop fry being siphoned to the filter. Despite of this, around 300 were triving in the filter during weeks until I collected them. I found out a better "prefilter" desing, safer and doesn't clog... collecting fry from the filter is very time consuming! A submersible pump (Eheim 1000 liters/hour or 220 USA gallons/hour) protected by crate plates and a net bag recirculate the water through a home made 30 Watts UV clarifier to the pond.
    Therefore, no green water at all. The advantage is that I can monitor what is happening in the tank anytime and see how the egg development looks like and what the fry are doing. In addition, there are less probabilities of massive losses due to diseases, parasites, or poor water quality related problems. And culling tobies is feasible anytime.
    Massive filtration allows you to apply rather massive feeding while keeping water parameters in the safe values.
    I fed young fry using water from "cultures" of infusoria and Daphnia during the 3 first weeks.
    After that I had some losses because I added by accident egg shells the first time I used Artemia nauplius to feed the fry. Despite of this I still had several thousands of fry around one month after hatching, then I started culling.

    Greg (Bickal), your web page was superb! Plenty of brilliant ideas very well explained and illustrated. It is a pity you have had such a massive fry mortality.

    Kiefer, you are planning a very interesting experiment. Mud ponds provide incredible growing rates, but also you may have high fry death rates due to different factors that are not easy to control, included a very vast array of predators.
    Appart from that, is just plain green water the only miracle ingredient in the recipe?
    You can get green water made of a blooming of just blue-green algae (Cyanobacteriae) that are able to fix elemental nitrogen, so they are only limited by phosporous. They can thrive in rather clean water if it is still and temperature is high, but their nutritional value is c..p
    That green water would be very different to one mainly contributed by other algae species of superior nutritional value... Some fisheries specialized in clam species culture do have pure cultures of certain algae species, and mix them in controlled densities to feed the small clams. That is too much for us!
    What about minerals? You are right, they are important but can be supplied easily to some extent. Maybe not the same mix present in mud ponds, but surely a sufficiently good mix. Even some commercial vitamins do include a large number of minerals that are important for development (I'm using one of those with my Koi as well as dry clay powder)
    Anything else... ?
    Large mud ponds do have much more than green water in them, including a large amount of small live prey items highly digestible and nutritious belonging to many different species of animals and plants. Fry can be browsing high quality, diverse live snacks -almost non stop. I believe this factor play a major role determining high grow rates and intense colors in Koi.
    I really doubt that such a complex small ecosystem can be replicated in a relatively small and isolated tank.
    If you can control or at least meassure the availability of these live prey between the mud pond and the breeding tank with green water, your experiment would help to understand the relative value of plain green water (unicellular green algae) and live food and their effect on fry development. Of course you must have a clear picture of possible differences between the apparently similar "green water" from the mud pond and the raising tank, since they might be rather different in composition.
    Please Kiefer, keep us posted with your findings. I have learned a lot from your experiences during the last few months!
    All the best,
    Diego
    Diego Jordano
    Cordoba, Spain
    A.E.K. web site http://www.elkoi.com
    pers. web site http://es.geocities.com/estanqueskois/

  6. #26
    Oyagoi bekko's Avatar
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    The important thing is the combination of green water and the zooplankton it contains. Rotifers, brine shrimp nauplii, tintinnids, daphnia and many such creatures have the nutritional value of a plastic bag except when they are actively feeding on phytoplankton. By gut loading the zooplankton with phytoplankton, all the essential fatty acids are transferred to the fish fry when it consumes that zooplankton. Copepods and some other higher forms of zooplankton can be nutritionally complete even when they have not been actively feeding on phytoplankton. However, it is the phytoplankton which provides the bulk of the nourishment for copepods, rotifers and other zooplankton and gives them the energy they need to reproduce.

    Some species of phytoplankton provide better fatty acid profiles than others, but it is rare that a green water soup and the zooplankton community that develops therein, will not provide the nutrition that koi fry need. Bluegreen algae is seldom a dominant form when establishing a new greenwater ''bloom''.

    There has been a lot of effort put into developing artificial larval feeds. There are now quite a few to choose from. Many are pretty good in terms of their nutritional value but are impossible to keep in suspension and do not have the movement needed to attract the fry. To work at all, very small amounts must be added continuously and the uneaten portion (most of what is added) must be removed before it begins to decay and degrade the water quality. In short, none are as effective as live zooplankton in terms of fry growth and survival. They are supplements at best.

    Brine shrimp nauplii can be an easy-to-use source of live food and is readily eaten by fry. However, the nutritional value of brine shrimp nauplii declines rapidly (within hours of hatching) as their yolk reserves are depleted. To be nutritionally complete, the brine shrimp nauplii must be enriched, by feeding them green water, axenic phytoplankton cultures, Selco or other source of highly unsaturated fatty acids, before the brine shrimp are fed to the fry. Brine shrimp die after an hour or so in freshwater so must be added continuously. In addition, in a clear water system, the brine shrimp quickly loose their enriched nutritional value if they are not immediately consumed by the fry.

    The simplest way to overcome these problems is to use green water which has been managed to support a dense population of zooplankton. This is the way Mother Nature and most fish farmers do it.

  7. #27
    Tategoi
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    Hello Bekko

    Great info. This is what I am trying to artificially reproduce for next springs hatching. I have always suspected that exposure to these types of elements during the first 3 or 4 weeks of fry development can make a major difference in their future growth and color. There was a major difference in the size and color of the koi fry harvested from natural pond
    compared to second test group from same spawn raised in a more sterile enviornment. Although the second group were fed freshly hatched foods continuously and were provided excellent water conditions, their color and size paled in comparison to there pond raised siblings. I have since placed 30 or 40 3.5 month old koi from the second test group in the large artificial green tank. After only three weeks, their colors already show a marked improvment. Although I do not have the where with all to prove corolation between the green water and the color enrichment, seeing is believing.

    Welcome back Diego. Hope your trip was relaxing. Will catch up with u later as the winds a really starting to pick up here and I need to monitor the situiation around ponds for a few hours.

    Later, Kiefer

  8. #28
    Oyagoi bekko's Avatar
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    I am dragging this thread out of the cedar chest just to point the breeders to a some really good articles on fertilization and zooplankton management. Everything said therein applies to koi fry ponds.

    http://govdocs.aquake.org/cgi/reprin...04/6040230.pdf
    http://govdocs.aquake.org/cgi/reprin...14/6140140.pdf
    http://govdocs.aquake.org/cgi/reprin...14/6140150.pdf
    http://govdocs.aquake.org/cgi/reprin...25/7250110.pdf

    -steve hopkins

  9. #29
    Oyagoi koifishgirl's Avatar
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    Steve you are the best. Thanks for the info as I am sure I will need it.

  10. #30
    Jumbo gregbickal's Avatar
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    I cant wait for spring to get here !!! I never thought I would be wanting green water. And to think back in the day (when I didnt have a filter in my pond), I had this whole pond of "green gold"
    Attached Thumbnails Attached Thumbnails Comments on reaing koi fry in green water.-gazette1.jpg  

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