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  1. #1

    Koi Fry with bent spine at tail

    This is my second year breeding koi as a hobbyist. I have thousands of fry and have been separating them into different tubs, according to size, and feeding them what I hope is a high quality food. What I'm seeing in some of them is a kink right before the tail, so the tail points at a 45 degree angle to the left or right. I do not know if this is a genetic defect, or something that is going wrong with their diet or water quality. I've dissected a few that died (not sure if those had bent tails or not), and do not see any parasites under a microscope. It's sad to see, since the fish seem to be in otherwise good health. I would appreciate any knowledge on this subject. If it is a defect they were born with, is it common? None of my 5 adults have this defect. Thanks in advance for any help.

    Greg



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  3. #2
    Extreme Koi Member Rank = Supreme Champion Davej's Avatar
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    Quote Originally Posted by intokoi View Post
    This is my second year breeding koi as a hobbyist. I have thousands of fry and have been separating them into different tubs, according to size, and feeding them what I hope is a high quality food. What I'm seeing in some of them is a kink right before the tail, so the tail points at a 45 degree angle to the left or right. I do not know if this is a genetic defect, or something that is going wrong with their diet or water quality. I've dissected a few that died (not sure if those had bent tails or not), and do not see any parasites under a microscope. It's sad to see, since the fish seem to be in otherwise good health. I would appreciate any knowledge on this subject. If it is a defect they were born with, is it common? None of my 5 adults have this defect. Thanks in advance for any help.

    Greg
    Hi Greg...

    My thoughts are that this is likely to be an environmental issue, most likely caused by overcrowding and too much feed. I can only really give my experience based onwhat I have seen with breeding and raising fry but what I have seen is that ifI retain and try and grow too many then a common defect is that the muscle in the base of the tail tube appears to develop disproportionally with one side weaker than the other causing a twist in the tail. It is hard to spot when they are tiny but looking carefully you can spot it and as they get bigger itbecomes more clear.

    It could be genetic but I favour the above as I have experienced the fault with fry from the same parent set that have produced thousands of fry without this defect in previous years. Same tanks same feed, only the stock density being different.

    A second defect that appears to go handin hand is what I term “Gudgeon Head” where the skull and mouth develops defects with the head becoming overly rounded with the result that the mouth ends up rather more underneath the head looking more like a Gudgeon than a Koi.
    Last edited by Davej; 11-09-2017 at 08:04 AM.

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  5. #3
    Quote Originally Posted by Davej View Post
    Hi Greg...

    My thoughts are that this is likely to be an environmental issue, most likely caused by overcrowding and too much feed. I can only really give my experience based onwhat I have seen with breeding and raising fry but what I have seen is that ifI retain and try and grow too many then a common defect is that the muscle in the base of the tail tube appears to develop disproportionally with one side weaker than the other causing a twist in the tail. It is hard to spot when they are tiny but looking carefully you can spot it and as they get bigger itbecomes more clear.

    It could be genetic but I favour the above as I have experienced the fault with fry from the same parent set that have produced thousands of fry without this defect in previous years. Same tanks same feed, only the stock density being different.

    A second defect that appears to go handin hand is what I term “Gudgeon Head” where the skull and mouth develops defects with the head becoming overly rounded with the result that the mouth ends up rather more underneath the head looking more like a Gudgeon than a Koi.
    I do have a greater sized surviving spawn this year, but I also have twice the capacity. I realize that I need to sell more to reduce their numbers. This year has not been very good for sales, so far. If the first scenario is the case, can it be corrected with more frequent, or larger water changes? If so, how much and how often? Nitrates are low and Ammonia was never an issue. Can the problem correct itself over time, or will they grow up, always having a bent tail? The tub they were hatched in is 300 gallons. The other two tubs I separate larger ones into are each 150 gallons. Also, I've been feeding them 3-4 times per day. I did not have this many with bent tails last year. I do have more fish this year, but I also have twice the capacity. I do find dead fry every day, maybe 30-50, mostly in the 1/3 to 1/2 inch size, but a few larger ones now and then. It's hard to estimate how much to feed thousands of fish, but I do my best to estimate. The smallest ones eat a "fry food" that I got on Ebay that is:

    Ingredients: Salmon Fish Meal, Dried Yeast, Marine Protein, Spirulina, Kelp, Vegetable Products, Fish Oil, Lecithin, Calcium Phosphate, Vitamin Supplements: A, E, D-3, B1, B12 & Biotin, Stabilized Vitamin “C”, minerals and amino acids. Analysis: Min. Crude Protein 55% Min. Crude Fat 18% Min. Crude Fiber 2 % Min. Phosphorus 1.3%
    Last edited by intokoi; 11-09-2017 at 03:37 PM.

  6. #4
    Extreme Koi Member Rank = Supreme Champion Davej's Avatar
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    Quote Originally Posted by intokoi View Post
    I do have a greater sized surviving spawn this year, but I also have twice the capacity. I realize that I need to sell more to reduce their numbers. This year has not been very good for sales, so far. If the first scenario is the case, can it be corrected with more frequent, or larger water changes? If so, how much and how often? Nitrates are low and Ammonia was never an issue. Can the problem correct itself over time, or will they grow up, always having a bent tail? The tub they were hatched in is 300 gallons. The other two tubs I separate larger ones into are each 150 gallons. Also, I've been feeding them 3-4 times per day. I did not have this many with bent tails last year. I do have more fish this year, but I also have twice the capacity. I do find dead fry every day, maybe 30-50, mostly in the 1/3 to 1/2 inch size, but a few larger ones now and then. It's hard to estimate how much to feed thousands of fish, but I do my best to estimate. The smallest ones eat a "fry food" that I got on Ebay that is:

    Ingredients: Salmon Fish Meal, Dried Yeast, Marine Protein, Spirulina, Kelp, Vegetable Products, Fish Oil, Lecithin, Calcium Phosphate, Vitamin Supplements: A, E, D-3, B1, B12 & Biotin, Stabilized Vitamin “C”, minerals and amino acids. Analysis: Min. Crude Protein 55% Min. Crude Fat 18% Min. Crude Fiber 2 % Min. Phosphorus 1.3%
    Hiya, There will always be a few that are weeded out at selection, but if the problem becomes systemic then I haven't found a solution, even if the numbers are reduced massively the problem seems to continue to manifest itself - that's my experience anyway...

    The level of mortalities would cause me concern, I will always get some but these are mainly down to Tobies.

    Feeding is a difficult one and its easy to get sucked into feeding more feed as there are a load more fry to feed, thus increasing pollution levels from the uneaten feed, then when they don't grow you increase feed simply compounding the problem. in reality the amount of feed needed is tiny, a gram of artemia has a hundred thousand tasty snacks... Feeed does need to be matched size wise to the needs of the smaller fry and ideally needs to be introduced constantly... Mine of similar size are mainly on newly hatched brine that I am introducing with a dosing pump so that they have a dribble of feed constantly..

    At the end of the day it is a learning experience, sometimes I make the right call with them, other times I don't, its not easy but it is a question of trying to analyse your mistakes and trying alternates...

  7. #5
    Extreme Koi Member Rank = Mature Champion Andre Asagi's Avatar
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    No ammonia? What are you using to filter the fry tanks?

    Can you describe how you are changing the water?

    Can you describe how you move the fry between tanks?

    Do you have an air pump running? If so, how does the air manifest in the tank/s?

    Just trying to eliminate physical damage to the fry. A tiny fry could very easily damage itself in so many situations. I have only ever "bred" orfe fry but i remember having to move the airstone almost to the surface and it would take me hours to change water in order to minimise any current that could send fry crashing into the side of the tank.

  8. #6
    not fry, but I had 2 very small koi that were bent, couldn't bring myself to get rid of them so just left them, they both came back straight quite suddenly at different times.
    They are probably always going to be stumped in their growth or affected in some way, but some local will happily take them free of charge, and give them a life.


    p.s, im not saying you should just sit on loads of bent fry in the hope they come good, that wouldn't be the best course of action. I just thought it was interesting that they can straighten up again.

    Dave

 

 

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