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  1. #1
    Member Rank = Sansai Mirza's Avatar
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    how to save fry ?

    For a couple of years I have been working with a friend on breeding koi and we have some success , every year we are progressing with equipment and with the quantity of younger ones.
    Young fish (fry) are kept in separated ponds because we have more pairs and spawn them all separately .
    After spawning we take adults out and eggs remain in the pond , this year we did spawn in three separate ponds, we get a huge number of fry ...when I say a huge number I think really huge, it's impossible to count and the capacity of each pond is about 10000 liters (2199 UK gal )
    fry is alive for about 30 days and then begins to die

    Last year, we released about 200 pieces of fry into a pond capacity about 3000 l of water, at the end of the year we pulled out only 50 fish, the others disappeared ( died ) while they were large 1 cm..
    I saw some of the water bugs eating them alive ..simply, every year, we lose a large number of young fish that can not grow to 1 cm..

    We tried to keep them in 100% controlled conditions where there are no water bugs and frogs, but it did not succeed.
    water is from well, and we all prepare a month earlier before leaving adult fish to spawn ..
    We even used the tap water in one year but it happened the same 90 % of them die before reaching a size of 1 cm.

    we simply do not understand why this is happening, because the rest of the fish that survive grow quite normal in these same ponds and everything is ok with them



  2. #2
    Extreme Koi Member Rank = Supreme Champion Davej's Avatar
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    Quote Originally Posted by Mirza View Post
    For a couple of years I have been working with a friend on breeding koi and we have some success , every year we are progressing with equipment and with the quantity of younger ones.
    Young fish (fry) are kept in separated ponds because we have more pairs and spawn them all separately .
    After spawning we take adults out and eggs remain in the pond , this year we did spawn in three separate ponds, we get a huge number of fry ...when I say a huge number I think really huge, it's impossible to count and the capacity of each pond is about 10000 liters (2199 UK gal )
    fry is alive for about 30 days and then begins to die

    Last year, we released about 200 pieces of fry into a pond capacity about 3000 l of water, at the end of the year we pulled out only 50 fish, the others disappeared ( died ) while they were large 1 cm..
    I saw some of the water bugs eating them alive ..simply, every year, we lose a large number of young fish that can not grow to 1 cm..

    We tried to keep them in 100% controlled conditions where there are no water bugs and frogs, but it did not succeed.
    water is from well, and we all prepare a month earlier before leaving adult fish to spawn ..
    We even used the tap water in one year but it happened the same 90 % of them die before reaching a size of 1 cm.

    we simply do not understand why this is happening, because the rest of the fish that survive grow quite normal in these same ponds and everything is ok with them
    Hi

    I think it is a question of getting the number and the feed right.

    In well filtered tanks of 2000 gallons I can raise about 10% of the hatched fry from an 80+cm female.. If I try and raise more then it compromises the entire group, I don't get casualties but development and growth is poor. If I have lower numbers they grow more quickly.

    Are you tanks filtered? and do you change much water? Keeping the water in good condition is a challenge.

    Feed wise if there are too many fry then it is easy to overfeed, this compounds the crowding problem as it adds to the pollution of the tank - when the fish don't grow the temptation is to feed them more... This just makes matters worse... It is easy saying it than doing it but retaining less and feeding sensibly reaps rewards.

    You will always get some fry that gain the taste for their brothers and sisters and can munch their way through them at alarming rate. These fish "Tobies" may be a cause of the losses in the larger fry.

    Dave

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  4. #3
    Member Rank = Sansai Mirza's Avatar
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    thanks, every advice is welcome especially if it is from more experienced members and breeders. It's very difficult when such a large number of fish dies because there's a lot of money and effort. We even made greenhouses across a pond to keep the heat when winter comes..for now it seems like we're just throwing money

  5. #4
    Extreme Koi Member Rank = Adult Champion bowsaw's Avatar
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    they are broadcast reproducers, the fittest <1% survive, the rest fall away due to natural selection along the way

    if they are suddenly failing at 30 days, wha are you feeding in the run and how are you filtering?
    the slow pond build thread

  6. #5
    Extreme Koi Member Rank = Supreme Champion Davej's Avatar
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    Quote Originally Posted by bowsaw View Post
    they are broadcast reproducers, the fittest <1% survive, the rest fall away due to natural selection along the way

    if they are suddenly failing at 30 days, wha are you feeding in the run and how are you filtering?
    Does that not all change when we protect the eggs and the fry from the losses that would occur in nature?

    Dave

  7. #6
    Extreme Koi Member Rank = Adult Champion bowsaw's Avatar
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    yes, we save fish that would ultimatly not pass natural selection. thats how traits like the colours koi are, albinos, split fins and all the other wretched looking fancy goldfish are created.

    some of natures defects are pleasing and cause little risk to the individual when in a secure pond, others are not very pleasant and can shorten life expectancy, like some of those horrible looking dogs that have a list of health issues as long as your arm, due to continuing to drive for breed "perfection"

    the more saved in the eyes of some commercial farms then the more successful and ultimately the cheaper product to the end consumer. others will go much more for quality and weed out all those other angry mouths and produce animals that carry a higher price and fit more what has become the accepted colour pattern in judging circles. the better we are at keeping fish alive the more species we have gone and driven selective trait breeding, theres now so many morphs of clown fish that each the banding their wild ancestors have and commend prices of hundreds of pounds rather than tens that wild type are sold for. there are also other aquatic species that are now extinct in the wild and live on only via intensive aquaculture, so it will be all to easy to bugger of these species by selecting traits that would other wise be weeded out in the wild specimens
    the slow pond build thread

  8. #7
    Senior Member Rank = Supreme Champion RS2OOO's Avatar
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    When you say they die, do you mean you find dead ones, or do they just disappear?

    You mention they die after 30 days, but can't reach 1 cm. I'd have thought by 30 days they should be at least 3cm? They need a constant food supply and live food is most ideal where possible because uneaten food doesn't pollute the water.

    When breeding Goldfish I find the first 5 days after hatching is most critical and after that I have to keep culling every few days to try and reduce the numbers (spawnings typically only around 10,000 eggs and about 1/2 to 2/3 hatch.

    It seems odd that yours are staying alive for the first few weeks and then dying, which might suggest water parameters, being sucked into the filters or predators getting them.

    Are you breeding them here in the UK? What kind of bugs are eating the fish? Water Beetles and Dragonfly nymphs tend to be predatory to fry, if these are the problem have you looked at ways of getting rid of them?

    What do you do with all the fungus eggs? Do you get a lot of them? If so treating eggs with methylene blue will sort that out and prevent water issues later on, not sure if it will kill the predators as a bonus, but it will kill nitrifying bacteria in the filters.
    Last edited by RS2OOO; 05-08-2018 at 09:13 PM.

 

 

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