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Nurturing Sumi

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  • Nurturing Sumi

    I was reading more of Takayuki Izeki's writings from over a dozen years ago on cultivating coloration in koi, and thought I'd share some of his thoughts on finishing sumi.

    He described melanin pigment cells as being like baskets. Sumi pigment is continuously produced, but diffuses through the cell wall, like flowing through the weave of a basket. When the openings are filled with an enzyme, tyrojinaze, the melanin/sumi remains within and by cohesion the melanin becomes deeper in color. However, the enzyme is unstable in the presence of acid. As acid (free hydrogen, I presume he means) increases, the melanin separates and diffuses through the cell wall, and then sumi blurs.

    He also explained silicon acts as a catalyst to cause production of melanin, with certain underground water sources and cement ponds releasing silicon.

    Izeki also writes that high oxygen levels and low nitrates are important. He emphasizes that temperature is not as important as it seems. That is, cooler water does not improve sumi directly, but indirectly it can. During cold periods when feeding is reduced, less nitric acid is produced, which in turn promotes cohesion of the melanin. At the same time, nitrate interferes with the dissolution of oxygen from the atmosphere into the water. The reduced nitrates in cooler water due to reduced feeding & reduced metabolism increases the ability of oxygen to dissolve into the water and results in less acid being produced, all of which results in higher dissolved oxygen levels. Having oxygen below saturation levels impedes formation of sumi.

    Izeki blamed failure to regularly empty settlement tanks for contributing to production of acids.

    He also commented that stories of some mud ponds being better for koi with sumi than other ponds is likely due to the presence of underground water flows into the pond bearing silicon.

    I am not able to vouch for Izeki's assertions, but it does provide reinforcement for the old refrain: Maintaining water quality is the first priority in every aspect of koikeeping.
  • #2

    I'm glad you wrote that down for others to be exposed to. it will definetly help them better understand.

    Among breeders certain koi seem to do better in areas with a sand based
    soil rather than clay and vice versa. Silicon is present with sand and one of the breeders of my favorite koi, Hosokai often says he breeds asagi's
    dispite the fact they don't do as well in his clay based soil!

    In my seminars, I'm ofter quoted by my students in a joking manner
    "cleanliness is next to godliness and next to running a better koi pond".
    with your summation of what you learned about black, they and others will be able to see why I preach that gospel!

    There are different products for sale for koi keepers. one of them is "sumi power"...Gosh you don't think it has any silicon in it do you?( makes you want to go out and put in a sand filter) but seriously know that one traps so much and so efficiently that it's almost impossible to keep clean and begins to work against you! Ahhhh, the joy of koi!
    Dick Benbow


    • #3

      Hey Mike,
      Where did you read this!! I need to get a hold of these good sources, anything else interesting you got for reading?

      Best Regards,
      Alex Gibbs


      • #4

        Alex, that was from an old Nichirin magazine from the first year or so that Nichirin was published. You can find odd issues from time to time on Ebay and such. My personal opinion is that English language Nichirin from mid-90s and older generally have better substantive content. The most recent have the best photos, but can't trust them not to have been re-touched. .... In the early issues they included fish ads from the Japanese language version. Have no idea what the ads say!


        • #5

          Mike M:

          Thanks for posting the article, very informative... I remember reading an article where the breeder claimed that concrete ponds were good for sumi development... Concrete: SAND, rock and cement...makes more sense now...

          Here's the conundrum, many new concrete ponds are being sealed with epoxy compounds to better control pH... So I would guess that this cancels out the beneficial effects of concrete ponds...

          I guess the solution would be like Dick suggested, but instead of a sand filter, add another of Steve Castel's blue bins filled with sand in bags...

          Thanks for spending more of my money... Between you and Dick I may have to go back to work...The last time I read one of your posts, I had to go out and buy a nitrate test kit...Thanks to Dick and Maurice, I now have a bakki type shower...

          Aloha! Mike


          • #6

            Akai San: Thought bringing this old post back to the top might be helpful re: your question about pH & hardness.


            • #7

              how exactly does silicon help improve sumi, isnt silicon inert?


              • #8

                Excellent question, Alex. I wish I knew the answer! Izeki referred to it as being a catalyst, but that is a translation from Japanese, so cannot be certain the original writings suggest the same connotation. Anecdotally, there is much written about different soils and water sources of Japanese mud ponds affecting varieties of koi differently. The mechanisms involved are not explained in what I have read. In general, softer water with lower pH (still moderate) coincides with better color development in varieties in which Sumi development is not desired, such as Asagi. Harder water with higher pH (still moderate) coincides with better Sumi development. Izeki was explaining that silicon is an important factor whose presence coincides with higher alkalinity, higher pH; and that acidity is harmful to Sumi development.

                If I come across an analysis of some of the mechanisms involved, I will post it. I expect too little study of the matter for a proper scientific conclusion. The fish farmers of Japan tend to follow the traditional knowledge without having to learn the reasons behind the results. They simply know that a certain pond, or ponds in a certain area produce better Kohaku, or better Showa, etc. In agriculture generally, it is known that trying to alter soil characteristics to better suit a particular crop is a losing proposition. Soils tend to return to their original chemistry. ...Just like fighting the characteristics of one's source water is a continuing challenge.


                • #9

                  Mike, I can't spend long on this as I've just been called to dinner, but my views on sumi are a little hard.
                  To me if sumi needs developing in different water/ pond type, the sumi is not good to start with!
                  If a koi has GOOD quality sumi, it will show in what ever water it is kept in.

                  Not many koi with good quality sumi, that's the problem!!


                  • #10

                    Maurice: I understand your conclusion, but would very much enjoy your thoughts in more detail. I think it leads to discussion of the extent of breeding Sanke genes into Showa, and structure of pigment cells, and why the Sanke-type Sumi gives the lacquer finish, etc. Hope you have some time to share your observations/surmises.


                    • #11

                      Bringing up this old thread because seems timely once more. Maybe Maurice finished his dinner by now.


                      • #12

                        Something very simple that no one mentioned. Using a black background. Keep a koi with sumi in a black liner pond. Try putting it in a pool with a white bottom and watch the sumi disappear. The difference is quite dramatic.

                        If your desire to succeed is greater than your desire to fail, then you will succeed.


                        • #13

                          Originally posted by MikeM View Post
                          Bringing up this old thread because seems timely once more. Maybe Maurice finished his dinner by now.
                          Must be one hell of a meal.


                          • #14

                            Wow!! LIGHTBULB MOMENT!!! I've often wondered why sumi finishes better in harder water. But what about the HI? Isn't a high PH and harder water harder on the HI? I would appreciate much more discussion re this topic please!! Here to learn!!

                            So if I'm to understand the initial summary. If your pond has a higher PH and silicone in the water you are likely to have more stable and better sumi? OK so if you add calcimum bentonite clay to the system, does that count?

                            ...Oh, and lots of 02 also....
                            2010 Upper Midwest Koi Club Show
                            AKCA 4th Annual Open Show
                            July 31st, Aug 1st & 2nd, Minneapolis, MN


                            • #15


                              Very timely re-post. I too am curious as I have high Ph (7.8-8.0) and my Kh runs around 140 and Gh at or above 300. I have a mix of Gosanke and others as most do. I have approx. 10,000 gallons and notice that colors on some are not as I would like. Harmonizing with what Maurice had written before he went to dinner, oh so long ago, is that it appears that he his right to a high degree. Some of my fish have excellent sumi and/or hi or both. Others seem to be more affected by the water conditions than others. Dick B talks about Hosokai and his breeding of Asagi despite his water conditions being less than ideal for that variety. I have had one of his Asagi in my pond for a year now and she is developing beautifully despite my water conditions. Incidentally, my pond is a converted swimming pool with no coating other than the original plaster.

                              Brutuscz - When you mentioned a light color pond and it's effect on sumi I had to smile. I remember when I first started this pond up, it was basically a white interior. However, after about 1-2 months, the fish regained their original sumi. That was in 2002. Now that the system has matured, the walls are very dark in color, the water is crystal clear, the fish are doing well other than some having problems bringing up the Sumi or maintaining Hi.

                              I have always been a believer in the theory about harder sandy bottomed mud ponds are better for sumi based fish such as showas/shiros. Now I understand why. I've always believed that, in theory, fish raised in the Isawa/Hiroshima area might do better in our harder water here as there water is supposedly much harder than that of the Niigata area. What do you guys think/know about this theory. Am I right or full of it?



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