Need help, massive beni problem in the whole pond

[saratogatan]

My pond that is. pond 6200g, filter 1400g. changed water 15%+, twice a week.

The story: more than a month ago, I noticed that all koi in my pond with beni started to show sign of receeding/thining beni, except 2 beni koi who are not affected. For example, the inazuma kohaku that won best in size in the April NorCal show is now a 4 step kohaku. The beni on another kohaku that used to be very thick was thinned to the point that it was light orange.

The things different this year from last:
- new koi food in late may. I used Ogata staple this year, plus hikari sinking wheatgerm. I used hikari wheatgerm last year.
- started light Ogata Silk power in mid Jun.
- koi spawned in early may, 6 spwaned. Last year, 1 spawned in Mid Jul.

On all of those koi, the trace of prior beni can still be identify, the tone of the 'new shiro' (more like light orange) is different.

I have stopped the ogata food all together for 2 weeks. started Hi-silk sweet potato+silkworm. The one kohaku with massive beni thinning is recovering that I can call those beni. The rest are yet to recover.

Question : What could be the cuase of my problem ? Is there any chance the beni maybe recovered ? Any specific food I need to feed the koi to stop the problem ?

I am way over-stocked. There are about 600" of koi in my pond, average 250 gallon of water per koi.

All suggestions are highly appreciated.

stan

[dick benbow]

Hi Stan, Sorry to hear of your problems.

If the beni was affected by a few individuals, I might think genetics but since a majority are affected it has to be conditions. I can't honestly think it's food. Usually when dealing with beni, if it fades awar chances are poor for recovery.

So the only other thing the koi have in common is the water. Could you run a battery of parameters and report them to us. The more the better but be sure and include PH and GH/kh.

other then the beni are we ok skin wise. no sores or lesions ( sometime heavy metals can create problems and you wouldn't think of them until you test for them....copper especially)

this is a pretty savy board so you'll be able to get some qualified feedback

[aquitori]

Tan forgot to tell you guys his pond gets more that 10hrs of direct sunlight.

I know during summer months Tan's area changes water source too...

[Jeff Speck]

pH swing ?

[dick benbow]

that combined with too much sun will do it. Sounds like we need a PH reading in the am and Pm to see how much the swing is and make a request for a sail cloth of some type to provide shade for the pond. thanks aquitori for filling in some of the blanks.... Jeff I think we're on to something......

[saratogatan]

The pond water is super hard, so ph swing is very unlikely. I have not done water quality test this year as everything looks normal. i am using the same water company, and thye claim to keep PH between 7.2 and 7.6.

the big kickers are the 2 beni koi, they are the baby of 1 or 2 of those affected, but they are not affected. The second kicker is the koi with thinning beni recovered somewhat after I switched food.

I will do some water testing tomorrow.

stan

[saratogatan]

more info, there is a wooden bridge over the pond, koi hide under the bridge during the day.

The pond is getting air from a 40l and a 80L airpump, plus a waterfall and stream. So, there should be enough oxygen in the water.

BTW, when I get to the last pallet of the Ogata staple, I found quite some dead bugs in the residual. I should have paid more attention to the food, but the food was supposed to be some new shipment thing.

other than beni, everything looks OK, no wound no flashing. No koi have been treated for a long time, (5 months +).
stan

[saratogatan]

mor on sun light, We are yet to get 10hr of direct sun on the pond. I expect the max to be around 8 hr as the new addition we just completed will block the sun after 6PM.

BTW, most of those affected have spent at least 3 summer in the pond.

stan

[MikeM]

Any new/different growths of algae or other 'stuff'? (There is a blue-green algae which can have weird effects on fish that consume it, although I do not recall reading anything about color loss.)

Invest in a full water analysis at UGA or elsewhere to see what might be unexpected. ...I'm wondering if there was some one-time release of something into the water system. There are times when a super-charge of chlorine occurs, maybe something else was used at some point?

If the bridge is new, then I'm wondering about whether it is treated lumber, or if recently painted if there were fungicides (copper/arsenic/???)

Just some floating thoughts.

[schildkoi]

Although I haven't had an issue with beni loss for some years now, in the past when I did, I attributed it to one of four things (or combinations there of). First, unstable water parameters creating "bouncing" effects in things such as Ph, temps etc. Second, less than optimal genetics. I was buying much cheaper koi back in those days. Hard beni, almost purplish (ges back to genetics) that was less elastice. Finally, the premature use of color food, having an almost burning out effect making the koi peak to fast.

Not sure what, if any of these, are related to your issues Stan but thought I would throw them out for you.

I have had issues (that I can at least relate to) due to sunlight and we had a lot of it both in Dallas and OKC....the Dallas pond was 6' deep and the final OKC pond was 4' deep.

Steve