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Thread: A Ramble About Selecting Tosai For Future Size

  1. #1
    Daihonmei MikeM's Avatar
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    A Ramble About Selecting Tosai For Future Size

    In another thread I mentioned that a tosai Kohaku I selected did not have the appearance of future jumbo. I've been asked what I look for in predicting future size. There are a number of traits that get mentioned when people are predicting future growth. Commonly, it is said to look for the tosai with large heads, wide heads and big mouths. People do that and end up with a koi that reaches only 65cm and get confused or disappointed. They picked the one with the biggest head. The mouth seemed wide. Something is wrong. The pond must be too small. They need to feed more food or higher protein. More water changes?.... the guy on the internet said lots of water changes is the key to getting growth.

    Any of those things may have contributed to the disappointing small adult size, but perhaps not. The hobbyist may have gotten all the growth the genetics of that koi allowed. So, the 'big head, big mouth' thing is wrong? No, not necessarily. It's a matter of relativity.

    When hobbyists are selecting from a batch of tosai, it is inevitably a batch of similarly sized fish. Is that how koi grow up? No. In every spawning, after all the culling, the breeder ends up with tosai of remarkably different sizes. Despite all receiving like care, some will be, say, 10 inches (25-27 cm). Some will be in the 7-8 inch range, some will be down in the 5-6 inch range. There might even be some still only 3 inches if the breeder did not cull them for being such slow growers. The total number of koi in a spawn that will ultimately reach a jumbo size of 85 or 90cm are few. Do you think the few will be in the group of tosai that are in the 6-7 inch size range, or are they going to be in the group that is 9-10 inches in size? If the batch of tosai you have to select from are all in the 6-7 inch range, you've already missed the opportunity to select from among those more likely to reach jumbo size. You may be disappointed that the one with a big head/big mouth only reached 65cm after years of care, but its siblings may have only reached 55-60cm. It was not your care that resulted in your disappointment. You actually did well with the selection and genetics.

    So, you need to pick the biggest tosai out of the spawning to get that jumbo you want, right? ...No, not necessarily. The biggest may well be male. The males tend to grow faster and stop sooner. Males can have big heads, too.

    A week or two ago on another board, Dick Benbow posted some thoughts on selecting tosai for future size which differ a bit from the conventional:

    "My experience has found many tosai's put out in the mud to create jumbos and actually achieve the status end up sulking the next year despite genetics. When I choose tosai to go out in the mud, I very rarely choose those that are biggest in the bunch. Rather look for something a bit smaller than the biggest that grow to average size that first fall but then take off the next year, that I attribute to genetics."

    Whether your experience consistently matches Dick's observation, many have observed koi go through growth spurt years. And, among tosai, there is the 'tobi effect'. A few tosai grow rapidly, consume an undue proportion of the food, leaving higher quality koi smaller than they could have been. The tobi fry are typically low quality. However the same effect can occur among young koi kept with insufficient food or space for all to develop fully. If the initial greenwater foods on which fry get their start were not copious, the size range can be considerable after just a couple of weeks and the dominant fish are not necessarily the ones with the genes to become super jumbo.

    So, are the purpose-made jumbo tosai the way to go to find the future 95cm monster? Maybe. But, how did the breeder select the koi given the high-growth treatment? And, is the batch of jumbo tosai actually the smallest batch of all those selected to get special treatment? If the breeder gave 100 tosai special treatment and 80 grew to 45cm, the 20 that only reached 25-30cm are not actually jumbo at all. You might call them the 'mini-jumbos' And, if the 100 were randomly selected out of a batch of the breeder's 200 best tosai, the tosai with the best chance to become super jumbo may well be in the 100 not given a warm winter of high protein food. That 100 may be just 20cm, but destined to be as large as the siblings being marketed as $1,500 jumbo tosai. I've been told there is one breeder who does not believe it is good to force too much growth in tosai, but likes selling high-priced tosai. So, I've been told, that breeder selects his top dozen or so to get normal winter care and then to the mud, and turns the second tier into jumbo tosai. I don't know if the story remains true.

    Last March I acquired 4 tosai. Three were nice 20+cm Showa tosai, which have grown like crazy the past two months. The fourth was a 26-inch (66+cm) tosai. Yes, a tosai sized like a large nisai. She is a Sanke with a long, but not wide head. Her mouth is not particularly large for a koi that size. Her body is very slender with great height. Viewed from the side, her shape is rather like a knife blade. She had a couple of siblings given similar fast-growth conditions who had comparatively massive heads, larger mouths and body frames showing future bulk. They were also very long, at least 60cm. She has grown over the past two months, but I've not measured her. She darts through the water as fast as those 'little' tosai Showa, truly cutting through the water like a knife. I expect she will become very large in time, but perhaps not. Matsunosuke genes are evident in that long, narrow body. So, we'll see.

    The fun is in the journey and trying to do the best you can with what you have.
    Last edited by MikeM; 05-16-2014 at 10:24 AM.

  2. #2
    Sansai nivek's Avatar
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    Awesome writeup Mike and to support your views, here is a photo showing 1.5mth old fries from the same spawn having vast size differences. Its articles like these that provides guidance to noobs like me when it comes to tosai selections.

    A Ramble About Selecting Tosai For Future Size-10295477_10152389088264362_3635850534534532998_o_1.jpg

  3. #3
    Jumbo RobF's Avatar
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    My pond spawned in April. I took a few eggs on a twig and dropped them into a pickle jar, 13 hatched and I moved them to a trifle bowl and then to a punch bowl. I fed them on a bit of string algae and a cup of scummy water a day. They have grown well and are fascinating to watch as they change. There is an average size, a tobi, and a tiny fry. From the same mother (fathers uncertain) the size difference between tobi and tiny is double in length and probably 20 times in mass. Tobi is just a fat yellow fry, Tiny is white with intriguing color development. I remember reading that Hasegawa said of his kohakus that from the small ones came the best and that if he (accidentally) let the weakest 10% die the year would be lost.

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    Oyagoi Eugeneg's Avatar
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    One day at dinner I asked Maedo San all the same questions and expected a lengthly reply as there was a long hesitation.
    Finally Disuke translated his short explenation. " Just like people large parents produce large babies "
    So what size were the parents of your grandchampion ?
    Regards
    Eugene

  5. #5
    Oyagoi RayJordan's Avatar
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    Mike I enjoyed your comments about selecting tosai for future size. Some of the things I have learned about this topic are:

    If you want a jumbo koi you need to start with offspring of jumbo parents. Both parents need to be Jumbo sized males and female. However the offspring of jumbo parents will also produce all sizes from runts to jumbo when fully grown. The tobi's (fastest growing fry) will often be male and while they were the fastest growing fry they will not end up to be the largest adult koi. Koi that grow at a above average rate for a large number of years are usually the ones that become jumbo over time. Of course in order to reach their full genetic potential they need to be properly cared for as they develop and especially their first 3-4 years. Top tier breeders know how to spot the tosai that will likely grow to be the largest from each group of fry. They might miss some that will develop in an unexpected way as far as pattern goes but they know quality and conformation and they make very few mistakes on the fundamental quality of which koi to keep and grow another year and which to sell now.
    Disclosure:These opinions are based on my experience and conversations with persons I consider accomplished koi keepers and do not reflect the viewpoint of any organization.

  6. #6
    Oyagoi yerrag's Avatar
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    In short, tosai selection is a minefield. But don't let it keep you from crossing. The leprechaun with the pot of gold is waiting at the other end.

    It is when I'm in the throes of excitement seeing a tosai I like that I step back, hold my breath, and confront my doubts. Is this the proverbial low-hanging fruit? Why did others pass on this? Is this too good to be true? Then as I hem and haw, someone swoops down and snatches the tosai from me. A nagging thought is the aftermath-did I miss out on a good find? Or was I prudent enough to not risk a poor purchase? Overanalyzing? Then again, I think about my well-stocked pond, and about not pushing the pond to its limits. Perhaps next time when the dealer imports a new batch-I will shop again. By then, I would have found a good home for my culls.

  7. #7
    Sansai almostgeorgia's Avatar
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    Thank you all for the interesting comments on jumbo tosai selection. These are some helpful insights as our local koi club prepares to make our choices in our annual 'Grow-Out'. This year we'll be working with (and hopefully learning from) a nice grouping of sanke from Sakai.

    Is there anyone more optimistic in the world than the koi hobbyist who carefully selects a few chosen tosai each Spring in hopes of raising up a beautiful fish, maybe even to show-worthy status someday?

  8. #8
    Daihonmei MikeM's Avatar
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    Quote Originally Posted by almostgeorgia View Post
    Thank you all for the interesting comments on jumbo tosai selection. These are some helpful insights as our local koi club prepares to make our choices in our annual 'Grow-Out'. This year we'll be working with (and hopefully learning from) a nice grouping of sanke from Sakai.

    Is there anyone more optimistic in the world than the koi hobbyist who carefully selects a few chosen tosai each Spring in hopes of raising up a beautiful fish, maybe even to show-worthy status someday?
    While this thread is about selecting for future size, if the goal is an affordable beautiful koi, thinking small may be more helpful. Many breeders have a cut-off size for tosai that will be kept another year. The 'keepers' are typically larger tosai since these will be more profitable as nisai than some runt. The tosai under the cut-off size get sold off, often in bulk. So, tosai above the cut-off size have had the best selected out. The ones below the cut-off include high quality ones that have not grown well. They may never be jumbo, but can be beautiful. And, perhaps more suitable to the size of pond. Think about a 7-year old koi competing in size 5.

  9. #9
    Jumbo Akai-San's Avatar
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    I think everyone knows that selecting tosai is already sketchy when looking for high quality koi. And then trying to select high quality JUMBO koi from a batch of tosai that has been released for early sale is even more remote. I agree with Mike in that the breeders will have already culled the tosai that he believes will not make it to his next level. But, I'm certain that each breeder has their standards for the year (some years better than others). However, I do think that when a breeder sees "high quality" in a koi (big or small), he will give it the benefit of the doubt to move on and possibly catch-up in the grow-out. Unless, his standards for the year are sooooo high, I do not believe they would trade size for quality. But I am just guessing and know nothing about what is important to each breeder.

    Now that I have my own grow-out going on, I can appreciate the larger sized Tosai as they toss and tumble with his smaller sibblings. In a short amount of time from my observations, I've noticed that the larger tosai is actually creating more distance between himself and his brothers. They are all growing, but the larger kohaku appears to be growing faster, longer in length for sure. I wonder in smaller numbers, do koi have a pecking order? Much like wolves, is there an Alpha?

  10. #10
    Oyagoi RayJordan's Avatar
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    It might be helpful to learn a bit about Tobi's as they are called in Japan or Shooters is a term also used in various fish farms. Survival is a key element in nature. I any group of koi fry there will be a variety of sizes even though they are all exactly the same age. Within a few weeks of the hatch there will be very noticeable size differences. The larger fry will begin to eat the smaller fry which allows them to grow even larger and faster. Nature's plan is very simple to speed up the growth process to allow some koi to reproduce as early as possible to insure the survival of the species.

    At the first cull the tobi's and runts will normally be removed to allow the more normal sized koi to survive and develop to their ability. But nature is persistent and at the next culling about one month later there will again be a completely new group of tobi's that have developed. Mother nature uses a ruthless culling method system to insure a few of the stronger babies will survive to reproduce but avoids overpopulation via predation, etc. Yes, there is sort of a pecking order in an established group of koi but it is more subtle than a wolf pack.

    Koi breeders have a completely different agenda than the natural order of things. Breeders cull for elements like body shape, size, and beauty, etc. These are recessive genetic traits rather than the dominate natural path of only let the strong survive. It has been said that if a breeder loses even 20% of their fry before they are culled at various stages of development the very best potential koi will be lost as the best are typically the weakest as babies. Another reason to removed the tobi's as soon and often as possible.

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