Will the sumi ever come back up?

[KoiCCAPW]

I have a pretty good shiro bekko that is hiding his sumi.
He's about 3-4 years old, and the second year had some decent sumi spots. Last summer it went down into the skin. You can still see them under the skin as grey shadows and each has a pinpoint of black that shows in the upper layer, but most of the patch is underneath. What are the odds that the sumi will come back up to the surface layer? Sorry I don't have a pic.

I've heard hard water can affect beni, but how about sumi?
It's a concrete pond, well matured, maybe 1,000 gal., and our source water is fairly hard also. pH is usually about 8, and KH is about 300, Gh 180+. 0 ammonia,0 nitrate, 0 nitrite.
10% water change(w/ cloram-x) about every 2 days(there's a slow leak), 20% with backflush about once a week.

Is there anything I can do to encourage the sumi to come back up?

[KoiCop]

your water readings tell me it should be good for the sumi, so I think you've got a chance it comes back strong. Good luck, Don

[koiczar]

Hi Barb

Your water is very similar to mine (surprise, surprise). However my Kh and Gh readings are reversed - Gh at around 300 and Kh at around 120-140. Sometimes sumi will go down and come back for the first 4-5 years and then settle. Sometimes it just goes down and won't come back. If this is a male fish, there is a possibility that it finished early and is just starting to decline. Mine is 8-9 years old (owner couldn't tell me when I bought her but thought she was 2 at the time). The last couple of years her sumi has been in decline but now seems to be holding but at a lesser quality than before. Someone mentioned something interesting on a different thread and I can't remember who it was. Only that there might be some trace elements or minerals missing in our water that would help the sumi develop better.

Mike

[MikeM]

Several decades ago the Japanese Inland Fisheries research institute studied what it was in hard water that made Sumi heavier compared to soft water. The key element identified was silicon. This may explain why mud ponds in sandy areas have been identified as good for Showa, while clay ponds elsewhere have seen to produce better Kohaku. Typically hard water has higher levels of silicon. In theory there could be low levels in hard water since "hardness" is measured without regard to silicon levels. Since silica is fairly ubiquitous in mineral composition, it would seem to me that this would be about the last thing to worry over. But, it is theoretically possible.

Some wild speculating to energize thinking: I would speculate that if a koikeeper had consistently poor Sumi development, but a neighbor had good Sumi development using the same tapwater, that there was a difference in husbandry and it might relate to use of clay. Clay mud ponds are often correlated with weak Sumi development compared to ponds in sandy soils. The Sumi comes up more dramatically when the fish raised in a clay pond are placed in a concrete holding tank. The water in these tanks is often drawn from the same source as the water filling the mud pond, and there is a continual flow which limits any change in hardness. But, there is no clay. The capacity of clay to adsorb mineral content from water could involve silicates being removed from circulation. ...This is pure speculation on my part. I've not seen any studies on the subject.

[dick benbow]

Many moons ago there was a dealer in the Portland,Oregon area, jerry harrants, who could bring out sumi. We lost him a few years back but remember his contribution to the hobby with awards named after him given at the show each year. As I recall he finished his filtered water by running it thru a final stage of #2 silica sand (down flow)

[MikeM]

That is very interesting. Possibly an unintended side effect of polishing the water. I'd not want to jump to a conclusion, but it is consistent with the idea that silicon strengthens the walls of the cells where melanin concentrates so that it becomes more intensely and visibly black rather than dispersing throughout the tissue. I got myself lost in chemistry articles a couple of years ago trying to understand the idea and never got back to it.

[dick benbow]

He would backwash this filter quite often to keep it clean and annually replaced the sand. I never did learn if it was to keep the silicon level up and fresh or to make sure nothing bad was being trapped in the sand

[mojo]

Quote: Originally Posted by MikeM Several decades ago the Japanese Inland Fisheries research institute studied what it was in hard water that made Sumi heavier compared to soft water. The key element identified was silicon. This may explain why mud ponds in sandy areas have been identified as good for Showa, while clay ponds elsewhere have seen to produce better Kohaku. Typically hard water has higher levels of silicon. In theory there could be low levels in hard water since "hardness" is measured without regard to silicon levels. Since silica is fairly ubiquitous in mineral composition, it would seem to me that this would be about the last thing to worry over. But, it is theoretically possible. Some wild speculating to energize thinking: I would speculate that if a koikeeper had consistently poor Sumi development, but a neighbor had good Sumi development using the same tapwater, that there was a difference in husbandry and it might relate to use of clay. Clay mud ponds are often correlated with weak Sumi development compared to ponds in sandy soils. The Sumi comes up more dramatically when the fish raised in a clay pond are placed in a concrete holding tank. The water in these tanks is often drawn from the same source as the water filling the mud pond, and there is a continual flow which limits any change in hardness. But, there is no clay. The capacity of clay to adsorb mineral content from water could involve silicates being removed from circulation. ...This is pure speculation on my part. I've not seen any studies on the subject.

last spring i have 6 dianachi (?) showa, 2 just fade like hell, 4 the black come up so strong. In the same pond. ?????? just my experience

[dizzyfish]

I got both of these Shiro Utsuri last year about the same time. One is a male and the other was unknown. One is from Marusho and the other from Sekko. On one the sumi has faded, or the other it has improved. They were kept under identical conditions. Can you guess which one is from which breeder?
Mitch

[MikeM]

Mojo: Sumi development is dependent on genetic factors as well as environmental ones. It will vary. There will also be variance at different ages as part of the normal progression. Nonetheless, it has been observed over periods of decades that certain ponds, or the water in certain areas, produces stronger Sumi than elsewhere. Part of the challenge of predicting the future of a koi.