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Valued Contributor
Posts: 765
Registered: ‎03-09-2010

Lost 2 large koi in the last 2 days-Help!

 

We have a 5,000 gallon pond. A large pump pumps water a foot into the air, and then it falls down into the water. The weather for the past 3 weeks has been in the 90s. No rain for a month, but we were adding to the water from our well. We have had some rain for the past 3 days. I know the oxygen level falls at night- but for the life of me, I am not understanding what is happening. The pond is seriously overcrowded with goldfish-we had around 8 koi. ( I am waiting till the weather cools off in Sept to catch some goldfish and set them loose in a pond at a local winery- we know the owner and he said it would be fine) The largest koi that died was a butterfly koi, the other that I found this morning was a beautiful orange one that was slightly smaller at 12".

I had to leave early this morning and babysit my grand daughters in another city, so I instructed my husband to drain some water and add some new- I know that cold water has more oxygen. He also cleaned the pump impellers and lowered the water level in the pond, so that the water goes higher into the air- in hopes that there will be more oxygen. I just got home-it is 8:30 pm. Should I go out and check the ph level and see if it is high? I have some vinegar that I can add if it would help. Is it barometric pressure that is doing this? I don't know what else to do. I feel so helpless.

Honored Contributor
Posts: 12,317
Registered: ‎03-09-2010

Re: Lost 2 large koi in the last 2 days-Help!

@rosehill....I am sorry you are losing fish, Loi are beautiful.

We also have a fish pond, with gold fish only and not near as big as your pond.

 

I only have a few thoughts...Have you been over feeding your fish during the hot spell? ...you probably know this...the more you feed them the more waste in the pond, which could cause problems.

 

Do you have oxegenating plants in the pond?

 

Is there enough room for them to swim?...I know that earlier this summer the plants in our pond were not growing at all but they took off and I have had to take quite a few out to make room for the fish to swim and not feel crowded or stressed

 

I hope you can find out what the problem is...call you pond store in the morning for professional advice!

Let us know how things turn out!

Valued Contributor
Posts: 645
Registered: ‎03-10-2010

Re: Lost 2 large koi in the last 2 days-Help!

If your pond is overcrowded with goldfish, you need to reduce that population immediately.  Goldfish are rather dirty fish to begin with, but overcrowding in fish tanks is deadly no matter the species. I don't know for sure if that is causing the problem, but when my father had a tropical fish business, he was adamant that you never have too many fish in a tank. Hopefully someone with more knowledge witl chime in soon.

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Trusted Contributor
Posts: 1,417
Registered: ‎04-08-2013

Re: Lost 2 large koi in the last 2 days-Help!

@rosehill ~ I'm so sorry to hear about your koi.  I also have a pond in our backyard, about 1,000 gallons.  This will be our third upcoming winter with a pond.  We have four koi and one goldfish ~ the goldfish is actually the largest, almost a foot long!  I bring this up because I worry about them constantly.  I keep a net over it because I spotted a heron in the backyard this past Spring.  Luckily he or she went away empty-handed.  We also have raccoons that frequent our yard.  Do you think it's possible that something is coming by and stressing them?  Does it look like anything might have gotten ahold of them?  I agree with the others ~ please call your local pond store tomorrow and ask the professionals.  Please keep us posted and best of luck....

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Posts: 24,105
Registered: ‎03-09-2010

Re: Lost 2 large koi in the last 2 days-Help!

Typically this is an oxygen level issue on hot days. Pond aeration is a big issue for pond owners. I saw a photo of a greenhouse pond where the owners had something like twelve of the big Danner Air pumps plumbed together on shelves to supply aeration to the pond. The general rule with aeration is you can't have too much. 

 

Assuming there's no surprise, the lack of oxygen in the water is almost certanly the cause. Bigger fish get affected more by the lack of adequate oxygenation too, so it fits with the pattern of what you're seeing.

 

I find the water chemistry in ponds (especially big ponds) is typically pretty stable, so it's not likely an ammonia, or nitirite level issue or even a Ph issue. Those would be more prone to affect all of the fish and not just your biggest fish. I'm pretty sure your problem is an oxygen issue. The good news is there are large, powerful air pumps made for pond aeration that will prevent future incidents.

Fly!!! Eagles!!! Fly!!!
Valued Contributor
Posts: 765
Registered: ‎03-09-2010

Thank you, Gardenman. I think that it is an oxygen issue....

Thank you, Gardenman. I think that it is an oxygen issue. I feel terrible, because the fish that died were just as lively as one could want, in days prior. My poor fish strangled to death. I had to work today, so no time to post this morning. No dead fish today. 

 

Do you have a pump/brand to recommend? I always thought what we had was doing the job, since the pump pumps a large amount of water about 12'18 inches in the air with great force. It must not have been enough though. I am in the market for auxillary aeration.

Valued Contributor
Posts: 765
Registered: ‎03-09-2010

Re: Lost 2 large koi in the last 2 days-Help!

Thank you, Mom, catlover and Julie. No more dead fish this morning. I have checked the PH, and we took out and added new water-cleaned the impellers on the pump. 

 

When we have pets, it is our duty to take care of them properly. These fish didn't ask to be here. I brought them here. It was my duty to not let this happen. I have never had problems in the summer like this. Goes to show, that one can never sit on their laurels.

 

Winter has taken it's toll on our pond too. We had a pond heater go out last year and lost 2 huge koi that my boys bought me for my birthday over 20 years ago. This year, we will have 2 pond heaters in place and be more diliigent about checking. When snow is covering a pond, you have to physically go out and check on it-you cannot see trouble from a window.

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Posts: 1,417
Registered: ‎04-08-2013

Re: Lost 2 large koi in the last 2 days-Help!

@rosehill ~ Yes, I worry all winter long.  We have the deicer and a couple aerators that I check throughout the day and also go out and check before we go to bed.  We have an automatic generator as well in case the power goes out.  Our pond store sells an underwater camera that hooks up to your TV so you can see what your fish are up to.  I would love to get one but they cost almost $300.00 and don't know if I can justify it, lol!  My guess is they aren't doing much in the cold weather anyway.

 

On another note, I was doing some housework in our den this afternoon.  I looked out the back window to admire the pond and saw our neighbor's cat pawing at the net!   NOT HAPPY ABOUT THAT!!!!!  Thankfully, there is no way it can get to them with the net on it but really?  We've had a talk about this before as I have 3 large dogs that are frequently let out into OUR yard.  (Our yard is also fenced in).  I guess you can never be too careful...

Honored Contributor
Posts: 24,105
Registered: ‎03-09-2010

Re: Thank you, Gardenman. I think that it is an oxygen issue....


@rosehill wrote:

Thank you, Gardenman. I think that it is an oxygen issue. I feel terrible, because the fish that died were just as lively as one could want, in days prior. My poor fish strangled to death. I had to work today, so no time to post this morning. No dead fish today. 

 

Do you have a pump/brand to recommend? I always thought what we had was doing the job, since the pump pumps a large amount of water about 12'18 inches in the air with great force. It must not have been enough though. I am in the market for auxillary aeration.


The big Danner Pondmaster brand air pumps are the ones I see used the most. They come in a variety of sizes and power ratings. They put out a ton of air when combined with the right diffusers. It's hard to get enough oxygen into the water with just water pumps, you almost have to add air pumps to force air into the water to get enough oxygen in the water for bigger fish. Small koi and goldfish can gulp enough air from the surface to survive, but the big guys/gals have a much harder time.

 

When you look at professional koi growers they almost all have supplemental air added to their ponds. In some cases they have a lot of added air, so much so that the water is almost like it's boiling. The consensus seems to be that koi are healthier and more active given supplemental aeration.

 

I don't know how your pump/plumbing is set up but you might be able to get by with adding a DIY venturi aerator to the plumbing. This would simply be a small air inlet somewhere along the water flow where air would be pulled in through the opening and mixed with the water. It'll make the water a bit noisier but in a pond it's not a big deal. You can buy premade venturi nozzles for use in hot tubs that you can adapt for a pond, or you can totally DIY one. 

Fly!!! Eagles!!! Fly!!!
Honored Contributor
Posts: 24,105
Registered: ‎03-09-2010

Re: Thank you, Gardenman. I think that it is an oxygen issue....

While we're on the subject of you, a pet peeve of mine is pet shops starving koi to death. Koi of all ages should have a nice full body yet when you see them in pet shops they're often gaunt and haven't had a real meal in days. It's a stupid way to treat an animal. Pet shop owners will say if they feed them the fish will create more waste than their filters can handle. Here's a creative thought, buy a better filter and feed the fish! Rant over. You may resume your normal posting.

Fly!!! Eagles!!! Fly!!!