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Mystery Cause of Death of Large Koi

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  • #16

    Originally posted by MikeM View Post
    Last summer I lost a large koi, over 85cm with good bulk. On day one, her behavior was 'off', tending to hover near the surface.... closer to the surface and more still than the usual schooling in the current behavior my koi frequently exhibit. On day two, the hovering near the surface was nearly constant, with the koi moving only when disturbed and not drawn to food. On day three, she died. There were no outward signs of a problem. No parasites detectable, no redness or discoloration anywhere on the body, and the gills appeared healthy.

    Going back over my records from the past 12 years, this was the fourth such death in my pond. All four instances have involved full-bodied (but not bloated)female koi in excess of 85cm (two at or over 95cm). All were 7 years old or older (the youngest being 7+ and the oldest being 10+ years). From outset of hovering behavior to death has been as short as 3 days to as long as 5 days. None had parasites, and none had outward signs of anything being wrong. Only the hovering behavior signaled there being some problem.

    If there had been just one instance, I'd chalk it up to one of those inexplicable things that happen... That's koi for you. Always something. Now that it has occurred on 4 occasions over a period of 12 years, I have to conclude there is a cause that I should address. I can imagine and theorize about a dozen possibilities from heart attack to some mystery amoeba to too much of a warm climate, but that does me no practical good. And, without a full post-mortem autopsy (and who would have the experience to do such a thing??... too late now, of course), no definite cause seems likely to be established.

    Nonetheless, I am posting about this to see if there are others who have experienced it. Perhaps then it would be possible to determine common factors that might be relevant.

    ....As a side note, the loss last summer motivated me to re-home all the old bedraggled dowagers that had taken up space. (Except, I still have the warped Hariwake born in my old lily pond 24 years ago. Re-building can only go so far. )
    How often do you hear this.

    The partner tells the spouse, I don't feel well. Off he goes to bed.

    Next morning, here is your coffee dear.

    No movement.

    Died in his sleep peacefully.

    Garfield.

    PS Autopsy report. HEART FAILURE.

    Comment

    • #17

      Originally posted by coolwon View Post
      How often do you here this.

      The partner tells the spouse, I don't feel well. Off to bed.

      Next morning, here is your coffee dear.

      No movement.

      Died in his sleep peacefully.

      Garfield.
      Hmmm... some wisdom being imparted, but master, I do not understand.

      Comment

      • #18

        I've been discussing these mystery deaths outside the forum. Thus far, I have not had anyone say they had observed the same behavior shortly preceding a sudden death, but it seems it is not uncommon for folks to have had an older very large koi suddenly die with no outwardly observed reason.

        Consulting JR, his thoughts were that being in-bred carp, koi have inherent weaknesses which are exacerbated when kept in warm climates where they do not get four seasons. He points out that carp have huge variations in life span, from 25- 100 years in some strains of wild carp. But koi are inbred and shorter lived, with 12-18 years being about all one can achieve (with solid colored strains and throw back strains like Karasu and Asagi living lomger, in the range of 14-28 years). Add to that in-bred weakness and the lack of four seasons, all the 'little things' that happen in a pond from time to time ( power failure, over stocking, chlorine exposure, etc.) and it wears on the koi. JR suggested that aging and premature aging due to lack of a four season experience also show classic G.A.S. (general adaptation syndrome) like symptoms... in this instance homeostasis stress due to life style ( i.e., the closed system, long term diet, no winter season). "So it is possible that all this cuts some percentage off natural- unnatural life of an inbred koi. The larger the animal, the more likely the shortening . Not a size issue as much as a weight issue with no winter draining of storage." Like an overweight fellow lazing around munching junk food, organ failure becomes more likely. Some individuals will still live a long life, and some will have their life span notably shortened. JR's bottom line was that there was probably not much that could be done under the circumstances, and that as long as the koi are living to 10-12 years, it is part of the reality of having a number of koi and seeing end of life occur early in a percentage. "...the captive environment wears on organs-- low pollution levels effecting bacteria counts and wearing gills, kidneys and swim bladders over time. And carp as four season creatures are slaves to hormones. These effect metabolism and sexual organs big time. In the end, those organs/ systems show up in ovaries/ tumors, kidney, liver and gills. That's life for the aging koi- premature or aged."


        Another long-experienced hobbyist told me that every time he has a koi death, an autopsy is performed. He has found tumors that were not noticable externally, several koi with with enlarged gall bladders and some with impacted eggs not noticeable externally. While these findings may not point to the specific cause of death in a particular instance, they highlight potential contributing factors. His mystery deaths have mostly involved older koi.

        A second hobbyist informed me "I too do a necropsy on unexplained deaths. Sometimes there is no visible cause but many times ...the cause is obvious. One case the fish had chronic fatty liver disease. Nothing at all obvious from the outside, but clear once opened."

        To some extent it is comforting that others have had mystery deaths occur, sometimes sudden. Still, I am left questioning whether something peculiar has occurred in my pond, simply because I have had the same behavioral symptom occur on four occasions over a period of years, with death occurring within days after on-set of the 'hovering'. Nobody has said they observed the same thing occur. Perhaps the added stress of the warmest season on older, large koi triggers a speedy death? ...But, if the absence of Winter was the root cause, it seems to me that koikeepers in southern Asia would be familiar with similar occurrences.

        ....The mystery is unresolved.

        Comment

        • #19

          Not too long ago South Africa went through a period of frequent power outages and, during this time, I was told the story of an old large female that was handfed and obviously very tame. Koi keepers would generally keep airlifts and aeration going during power outages but power hungry circulation pumps can obviously not be run from backup power that easily. This female would sense that water circulation had stopped for longer than what is needed to clean the filters and she would then hover (not gasp for air) near the surface. Her owner claimed that petting her would often settle her and that he sometimes (against his better judgement I am sure) fed her small amounts of food which also settled her 'emotionally'. He believed that her hovering was her way of communicating distress over the sudden change to her habitat. Possibly too much for some to swallow but there you have the story.

          Maybe MikeM's fish hovered because they sensed that something was amiss.

          Comment

          • #20

            Consulting JR, his thoughts were that being in-bred carp, koi have inherent weaknesses which are exacerbated when kept in warm climates where they do not get four seasons. He points out that carp have huge variations in life span, from 25- 100 years in some strains of wild carp. But koi are inbred and shorter lived, with 12-18 years being about all one can achieve (with solid colored strains and throw back strains like Karasu and Asagi living lomger, in the range of 14-28 years). Add to that in-bred weakness and the lack of four seasons, all the 'little things' that happen in a pond from time to time ( power failure, over stocking, chlorine exposure, etc.) and it wears on the koi. JR suggested that aging and premature aging due to lack of a four season experience also show classic G.A.S. (general adaptation syndrome) like symptoms... in this instance homeostasis stress due to life style ( i.e., the closed system, long term diet, no winter season). "So it is possible that all this cuts some percentage off natural- unnatural life of an inbred koi. The larger the animal, the more likely the shortening . Not a size issue as much as a weight issue with no winter draining of storage." Like an overweight fellow lazing around munching junk food, organ failure becomes more likely. Some individuals will still live a long life, and some will have their life span notably shortened. JR's bottom line was that there was probably not much that could be done under the circumstances, and that as long as the koi are living to 10-12 years, it is part of the reality of having a number of koi and seeing end of life occur early in a percentage. "...the captive environment wears on organs-- low pollution levels effecting bacteria counts and wearing gills, kidneys and swim bladders over time. And carp as four season creatures are slaves to hormones. These effect metabolism and sexual organs big time. In the end, those organs/ systems show up in ovaries/ tumors, kidney, liver and gills. That's life for the aging koi- premature or aged."
            Mike, since you've been caring for koi for around thirty years, and you've re-homed a fewlarge old koi, I'm assuming that you've raised large koi (other than the 24-yr old hariwake) from tosai or nisai, and that prior to these past 12 years, which would be eighteen years of koi raising, you did not experience such rapid and unexpected mortality from large koi. Is that correct?

            I'm not convinced of JR's argument that because koi are four season fish, they would live longer in temperate countries. I think koi are adaptable to tropical countries, and would live just as long. If we allow koi to adapt to a different climate. Since our water temperature in the tropics and in Florida are still tolerable and even conducive to koi development, the one adaptation where we could help our koi is to give them food that reflects what is available locally. The oil composition of locally available food sources would be weighted towards being saturated, and that would be part of the adaptation needed by the koi. Feeding the koi something that is more suitable to temperate conditions would not help the koi adapt. Saturated fats stand up better to the higher temperatures in a tropical climate, in that there is less opportunity for the oil to be oxidized in the body. Free radicals from oxidized oil cause degeneration. Organ degeneration and cancer formation are likely to be accelerated.

            That still doesn't answer the question of how your hariwake and other re-homed koi are able to survive and live long years. Perhaps the rate at which they were fed in their early years had a significant impact. The large koi that died were fed intensively that gave them growth rates that allowed them to become large koi. They may not even have benefited from the four-season variation in temperature, so that their growth would not be hindered. Even in tropical countries, the koi go through hot spells where they practically fast (or eat little). Since there is much profit to growing jumbo koi in the race to have larger gosanke that would compete much better in koi shows, more attention has been given to size, and longevity may be the trade-off.

            My only gosanke, raised from a 15cm SFF sanke tosai to 81cm at 5 years, would be my test case for how a more in-bred koi would fare in a tropical climate. It isn't raised for size, although it grew quickly, and it is fed with plenty of coconut meat to increase the raito of saturated oil to polyunsaturated fats that are available in koi pellets. It still has very good skin, its beni is still youthful looking and soft, although the tradeoff is that it isn't thick. It wasn't bad such that it was able to win the jumbo award, and got a vote or two in the reserve GC award. Since I've had two koi die recently at 5 years old, I have to see how this koi progresses in the coming years. Survival is my main concern, followed by skin quality, then growth.

            If this koi survives and develops well, it would be my only example of how tweaking food for the local conditions in a tropical country would help. I don't know of any other koi keeper doing this, but I'm sure there are, as I'm sure there are keepers who would rather stay away from plain view. Koi keeping and developing great koi is a reward in itself. Many keepers just don't need to show their koi to prove themselves.

            I can get back to you every year on the status of my sanke, and hopefully, I would be able to buttress my case. And help you deal with reducing casualty with large gosanke.

            Comment

            • #21

              I happen to agree with JR that the lifespan of koi nowadays have fallen and I agree without slowing the metabolic rate of koi thru colder water temperatures, cell division limits are reached faster. I believe that if you keep on pushing the growth of koi improperly whatever that means, you somewhat cut short the lifespan. Years before it was not uncommon here to grow chagoi as fast as possible and in 3 to 4 years you have gotten a jumbo chagoi but only to find out that it wont survive more than 4 years. Nowadays, the average lifespan seem to have improved along with growth rates due to better food and water quality. Sizes of 1meter 4 to 5 y.o. chagoi is now possible. However I am pessimistic that these chagoi grown in eternal summer settings can live longer compared to 4 season environments.

              It is my understanding that koi bred to grow now could be tied to a shorter lifespan. In dogs, bigger breed of dogs have a generally shorter lifespan as compared to smaller breeds.

              In terms of food choices, food manufacturers also have been pushing for higher protein because of market demands. When before 28% was the norm, nowadays its could be as dangerously high of 50% just to push for that extra cm of growth and more bulky look at the expense of potentially hidden problems along the way that greatly reduced the mortality of koi.



              Diet does play an important

              Comment

              • #22

                Originally posted by yerrag View Post
                Mike, since you've been caring for koi for around thirty years, and you've re-homed a fewlarge old koi, I'm assuming that you've raised large koi (other than the 24-yr old hariwake) from tosai or nisai, and that prior to these past 12 years, which would be eighteen years of koi raising, you did not experience such rapid and unexpected mortality from large koi. Is that correct?
                Until my current pond was built in 2005, I did not succeed in getting many koi larger than 70cm (28 inches), one exception being the old Hariwake which was close to 80cm back then. When my current pond was built, I added several less expensive koi for learning purposes and began to add a better quality koi or two each year. With the population limited to 16 fish in 12,500 gallons, ones I had previously continued to grow past 80cm. So, it is only going back the past 12 years that I have had what I consider large koi. It would be wrong to think that all or many of these have had sudden deaths. That is not at all the case. Only the 4 I mentioned have had sudden death from undetermined cause(s). Others have been re-homed along the way or passed due to readily determinable causes. I would have to go back through my records to see how many koi over the past decade have reached 85cm and what occurred with each, but I do not think that would be helpful in trying to figure out what went wrong with the four mystery deaths. ...And, the Hariwake is not the only oldster in the pond. I have kept Vamp, a Marusada Showa of magoi lineage who is now 16 (maybe 17??) years old (I don't have my records with me) and around 85cm, if not longer, a beloved odd koi that still fascinates and thus still has a home. She was reviewed in a thread a dozen years ago when I was raising up a bunch of Showa to learn from.

                Comment

                • #23

                  Originally posted by sacicu View Post
                  I happen to agree with JR that the lifespan of koi nowadays have fallen and I agree without slowing the metabolic rate of koi thru colder water temperatures, cell division limits are reached faster. I believe that if you keep on pushing the growth of koi improperly whatever that means, you somewhat cut short the lifespan. Years before it was not uncommon here to grow chagoi as fast as possible and in 3 to 4 years you have gotten a jumbo chagoi but only to find out that it wont survive more than 4 years. Nowadays, the average lifespan seem to have improved along with growth rates due to better food and water quality. Sizes of 1meter 4 to 5 y.o. chagoi is now possible. However I am pessimistic that these chagoi grown in eternal summer settings can live longer compared to 4 season environments.

                  It is my understanding that koi bred to grow now could be tied to a shorter lifespan. In dogs, bigger breed of dogs have a generally shorter lifespan as compared to smaller breeds.

                  In terms of food choices, food manufacturers also have been pushing for higher protein because of market demands. When before 28% was the norm, nowadays its could be as dangerously high of 50% just to push for that extra cm of growth and more bulky look at the expense of potentially hidden problems along the way that greatly reduced the mortality of koi.



                  Diet does play an important
                  I believe you are correct that gosanke, particularly those from the leading breeders whose bloodlines produce the bulk of GCs over 85cm, have shorter life spans. The number that pass within a couple of years of winning GC at one of the 'world class' shows is high. It no longer surprises to hear about it. There does seem to be a weakness in the gosanke capable of reaching over 90cm. The meter long gosanke are rare, not just in reaching that length, but in staying alive after doing so.

                  I would not blame the protein percentage of food, but would not disagree that the constant heavy feeding is a contributing factor. I tend to think that my feeding practices contributed to the mystery deaths.

                  Comment

                  • #24

                    Originally posted by MikeM View Post
                    Until my current pond was built in 2005, I did not succeed in getting many koi larger than 70cm (28 inches), one exception being the old Hariwake which was close to 80cm back then. When my current pond was built, I added several less expensive koi for learning purposes and began to add a better quality koi or two each year. With the population limited to 16 fish in 12,500 gallons, ones I had previously continued to grow past 80cm. So, it is only going back the past 12 years that I have had what I consider large koi. It would be wrong to think that all or many of these have had sudden deaths. That is not at all the case. Only the 4 I mentioned have had sudden death from undetermined cause(s). Others have been re-homed along the way or passed due to readily determinable causes. I would have to go back through my records to see how many koi over the past decade have reached 85cm and what occurred with each, but I do not think that would be helpful in trying to figure out what went wrong with the four mystery deaths. ...And, the Hariwake is not the only oldster in the pond. I have kept Vamp, a Marusada Showa of magoi lineage who is now 16 (maybe 17??) years old (I don't have my records with me) and around 85cm, if not longer, a beloved odd koi that still fascinates and thus still has a home. She was reviewed in a thread a dozen years ago when I was raising up a bunch of Showa to learn from.
                    Given your experience Mike, and I hope you don't mind me asking, would you be more likely to think twice before bringing into your pond large sansai gosankes? It would have cost more to get them, yet for them to go so soon... would growing from nisai be the way going forward? Would you feel more confidence in longevity with a DIY large koi than buying a 3yr. old jumbo koi?

                    Comment

                    • #25

                      Originally posted by yerrag View Post
                      Given your experience Mike, and I hope you don't mind me asking, would you be more likely to think twice before bringing into your pond large sansai gosankes? It would have cost more to get them, yet for them to go so soon... would growing from nisai be the way going forward? Would you feel more confidence in longevity with a DIY large koi than buying a 3yr. old jumbo koi?
                      Well, obviously these mystery deaths are outside my experience... or, should I say, they are part of my experience from which I've not learned something I should learn. LOL.

                      Since the mystery deaths all concerned koi that I had raised for multiple years, I do not give much weight to them having been older than nisai when acquired. Transport stress was long in the past when they died. No doubt larger koi endure more stress in shipment (but those bags stuffed with numerous tosai shipped in bulk are surely far more stressful). I'd include shipment/transport stress among the many 'little things' koi endure in captivity, the cumulative impact of which was JR's point.

                      Comment

                      • #26

                        Originally posted by MikeM View Post
                        Well, obviously these mystery deaths are outside my experience... or, should I say, they are part of my experience from which I've not learned something I should learn. LOL.

                        Since the mystery deaths all concerned koi that I had raised for multiple years, I do not give much weight to them having been older than nisai when acquired. Transport stress was long in the past when they died. No doubt larger koi endure more stress in shipment (but those bags stuffed with numerous tosai shipped in bulk are surely far more stressful). I'd include shipment/transport stress among the many 'little things' koi endure in captivity, the cumulative impact of which was JR's point.
                        I hope that you will be able to find out the most likely causes of the mysterious deaths, and be able to get future large koi that will develop well and last long.

                        Comment

                        • #27

                          Originally posted by MikeM View Post
                          Consulting JR, his thoughts were ...
                          On the assumption that JR used to post as user JasPR, is there any way to convince him to join the forum again? He left after some unpleasantness which I do not care much for. He is a great teacher and the hobby is worse off without his knowledge transfer. He should come back and continue teaching. He is not the only super experienced guy on the forum but he is definitely missed. Anyone (MikeM?) that agrees with me and that can convince him?

                          Comment

                          • #28

                            JR's knowledge is missed, but he has moved on.

                            Comment

                            • #29

                              Last week, I had a bit of a pond crisis, all involving my 3 7yr old koi (which are just beginning their 7th year). None of them are gosanke - an 85 cm white asagi, a 75 cm shiro utsuri, and a slightly smaller shusui. My 6yr old 81cm sanke was beginning to show signs of being affected, but not as strongly as thse three. The remaining eight koi, beginning their third year, weren't affected.

                              We are at the beginning of summer, and water temperatures have gone up, and the sun has already begun its move towards casting a smaller shadow. The smaller the shadow, the more direct the sun is. The cool season is over. We have a different pattern here, where the coldest season goes directly into the warmest season, the cold season being brought upon us by the far reaches of the cold Siberian winter, yet the cold being tempered by the sun already beginning its rise over the horizon from December lows. The effect on a koi keeper like me is that we get a quick transition cold cold water temperatures into really warm water temperatures. The lowest water temperatures of around 23C around mid-February would reach a peak of close to 30C around mid-April, and the peak would last around 3 months at most.

                              The asagi and the shiro started showing visible redness on their skin, and their behavior changed from being calm to becoming agitated. The shusui became similarly agitated, although it was hard to see visble signs of redness on the skin. They lost their appetitie, and they began to swim a lot. The asagi would stay directly below the waterfalls, while the shiro would keep swimming near the surface by the pond walls. The shusui would jump more often, and I was just glad it didn't get to a point where I'd find him by the pond surroundings in the morning.

                              At first I thought I was late in putting up the shade sail, but upon further examination, I discounted this as a cause. The pond is bounded by the 2-story house on the west, and partially by the house on the north and south of it, and what is not shaded by the house is compensated by trees and foliage, so the direct sun only gets to hit from the east in the morning. Still, it is heavily blocked by a wall and palm trees. The only time the pond gets heavily hit by the sun is during the heavy summer months, when the sun hits directly overhead (where there is practically no shadow at its most direct exposure).

                              I thought I was already pretty good with my pondkeeping chores, and the water parameters are good enough for me, with ammonia and nitrite pretty much nil, whereas my kH has been under control with the use of an anoxic filter. I've been cleaning my filter bottoms as well as flushing the bottom drain. When I swim to inspect my koi, I do not detect any itch, which meant for me that there was no outbreak of pathogens. And when I siphon the waste from filter bottoms, I don't get to smell any foul smell either.

                              Anyway, I had salted the pond to slightly above .2%, and doubled the flowrate. The redness in the koi skin have begun to subside, and the three koi are acting more calm, although they aren't yet ready to feed. I'm convinced that my learning isn't done, and that I would be learning about caring for large and mature koi beyond their 7th year. They are more sensitive with each passing year, and this is where I begin to appreciate the koi dealer's words of wisdom to limit my koi population. There is a great need for a large margin of safety with these older koi.

                              As to the cause of the crisis, I can only guess that the higher water temperature made pathogens more active. And I think there's another cause that could have caused the pathogens to act up the way they did. I had started feeding them the solid leftovers from juicing fruits for my mom. I hand feed these koi these juicing leftovers (watermelon, cantaloupe, honeydew). I made sure they are fed into the mouth, but I think there were still some that went to the water column. In cold water temperatures, I didn't experience any downside. But with the water warming up, I may just also be feeding the pond pathogens.

                              Well, I'm just glad I caught this early. The koi are going to be nursed back to health. Feeding the koi manually gives me the chance to catch signs early and helps me keep things from devolving further.

                              Comment

                              • #30

                                Glad you got this under control - whatever it was. Would have been a bad way to start summer had things gone the other way ...
                                There is much written about how hardy koi are but I sometimes wonder? As you pointed out, I think the secret is in the safety margin that comes with low stocking levels.

                                Comment

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