I'm so upset! Two dead Koi! l

[AngelaM]

I think a lot of folks were caught off guard by how hard this winter was, especially after a few mild winters. I don't know the size of your pond, but perhaps you could consider a cover next winter?

What do you use for a cover Tula? My pond is 20 feet long by 10 wide.

 

[sissy]

I see at few on here use solar pool covers and all you need is to make a hoop house and ly the solar cover over it .The hoop house does not need to be big just sturdy enough to hold u under a snow load

 

[MitchM]

Without a discussion and exploration of the facts, online reviews are someone's opinion, nothing more.

When there is no knowledge or understanding of water quality test results, filtration methods, stocking levels, knowing the amount of decaying organic buildup before winter, pond design or ice thickness and length of time covered , then trying to place the fault on any one thing does not help the situation and will lead to further fish deaths, only to blame something else next time.

I believe neither Colleen nor sissy have seen or used a pond breather and I'm not really sure they understand how they work. Pond breathers provide an active aeration method for ice covered ponds. Floating heaters are passive and can become iced over, no matter the wattage. Aerators work well providing both circulation and aeration, but are best for mild climates.

Total ice cover presents the most hazardous time for a pond because it basically shuts off any gas exchange that keeps the water in a survivable condition for fish.
We can certainly help AngelaM prevent fish deaths in the future, but we need to examine all aspects of the pond, starting with the information required as I mentioned above.

 

[brokensword]

actually KOI are MUCH more hardy than goldfish and do very very well in ICE COLD RUNNING water, the trouble comes when they run out of air under the ice and then they die first as they are larger and need more oxygen than goldfish. I have had my koi outside in below minus 40 temps since 1991 and never lost one and that is because I KNOW they need lots of oxygen and keep the water running with special underwater filters and pumps that can run all winter.
I did try to warn everybody about those pond breathers and did say many times that they may not work for extreme temps and large koi.....

disagree, Colleen; do some research first on gf and you'll see they can handle almost freezing temps (33 F) and koi are at 34. As I said, almost as hardy. No doubt being larger, the oxygen supply becomes more of an issue, so again, goldfish would be hardier during winter just because their size isn't as large. And you continue to promote running water but you also use a heater to help out. If you didn't, running the water during the winter would prove disastrous (imo) as you'd expose the lower levels of your ponds to even colder air, super cooling the lower depths and pushing the koi toward that 34 F temp. Without an air to water opening for oxygen exchange, fish will die after a prolonged period of ice coverage. Just the process of decay (which continues even in the cold) uses up oxygen.

To blame the breather is folly. As Mitch states; there's other factors that come into play. Fish can handle a couple of months completely covered and no air exchange as long as there's ample water volume (and depth) and little decaying debris. addy had a friend lose all their fish and they used only an aerator; do we blame the aerator? Would the fish have survived then not having an aerator? I doubt it, not if the ice was in place continuously for a long time.

Mitch lives and maintains a pond in MUCH more severe climate than we do here in Michigan. If he can keep a pond and its inhabitants alive with almost 5 months straight of ice WITH just breathers, I'm sure we here can too. And I'm sure he's got other factors involved but has taken care of those that would lower survival for his fish.

The breather is ONE way to insure a hole is maintained. Even if drifted over, the small pump and heating element would have kept the ice from forming inside the tube. And air transfer can happen through snow. So, more likely the size of the fish per volume+depth of water comes into play re their survivability. I'm betting goldfish would have made it in your pond...

 

[MitchM]

Goldfish can survive being frozen in ice, koi cannot.
I posted an article a while ago that shows how goldfish are able to do that.
https://www.gardenpondforum.com/threads/goldfish-cold-water-survival-secret-ethanol.21970/

 

[sissy]

I have never had a deicer freeze over and I have had mine from 2004 and only thing that killed the one was my mistake and a cat .The power cord froze and the cat I chased off the pond broke it .I trust what works and not everything new that comes out on the market .I don't care to loose my fish because they may or may not work .How many new things on the market these days have not been tested properly and have not been tested long enough before being marketed to the public .

 

[AngelaM]

I don't think pond size to fish ratio is a problem. My four Koi lived in a smaller pond for at least ten years. Mine is actually deeper and bigger. Decaying leaves could be a problem. My net did get weighed down and dipped into the water in one place. Should I start doing spring clean up now to prevent any further deaths? I guess I'll start by testing the water tomorrow but I'm with Sissy, I think it's best to use a couple different options incase one fails. These Koi have been use to their old owner tossing in a bubbler just for winter for years. I regret not sticking to that now. I like that the pond breather leaves a hole for gases to escape. It seemed to be working fine, even under a snow drift I could hear it doing its job. However I think the fish could've used more oxygen.

 

[Lisak1]

Well, I don't think that anyone could argue that more oxygen could ever be a bad thing. If you can see debris in your pond and remove it, that's also always a good thing. No reason to wait. But if it was a lack of oxygen that killed your other koi and these survived, they should be fine if the ice is gone. If it was something else that killed your koi, hopefully your remaining fish won't be affected.

Remind us - how many gallons is your pond? Did you just have the four koi? Or are there more fish?

 

[addy1]

I had 18 inch deep ice, measured, this winter. My 1000 gallon pond has quite a few fish in it, no deaths. All I used was a pond breather. I believe they do the job. This is my 4th winter with them, no deaths since I began using one.

Only goldfish/shubunkins. Largest around 12 inches

 

[AngelaM]

Remind us - how many gallons is your pond? Did you just have the four koi? Or are there more fish?

Hi Lisa, My pond is 2100 gallons. It housed the four butterfly Koi. They are all about 12" long. A black molly that is about 8" and a regular goldfish that is about 8" long also. Possibly a crawdad unless he moved on. lol

 

[brokensword]

I don't think pond size to fish ratio is a problem. My four Koi lived in a smaller pond for at least ten years. Mine is actually deeper and bigger. Decaying leaves could be a problem. My net did get weighed down and dipped into the water in one place. Should I start doing spring clean up now to prevent any further deaths? I guess I'll start by testing the water tomorrow but I'm with Sissy, I think it's best to use a couple different options incase one fails. These Koi have been use to their old owner tossing in a bubbler just for winter for years. I regret not sticking to that now. I like that the pond breather leaves a hole for gases to escape. It seemed to be working fine, even under a snow drift I could hear it doing its job. However I think the fish could've used more oxygen.

just realize that aerators do NOT put oxygen into the water in any measurable amount; it's the turbulence at the surface where this process mainly occurs. Once ice occurs and the hole created by the aerator narrows into slush filled, the only oxygenation occurring will be similar to what happens with a breather. I keep asking re gallonage and/or depth? Is this 20' x 10' actual surface area or liner dimensions when you got it? Is this pond sunk in the ground or elevated? Makes a difference. And whereas your fish might have survived before, they've probably been growing until the size they are now, and as they grow, their requirements go up. Can't relate year 1 with year 10, etc when it comes to this.

Leaves decaying can affect but I think it was adavisis who noted that leaves decay very slowly and probably didn't affect your pond this winter; if you have any decaying organics from the summer, that would be the worse offender.

And nothing wrong with having more than one option. The intense cold we had in December was not normal and more than likely is what caused a perfect storm of temp, oxygen, and fish size to collide.

Btw, cold water can hold much more O2 than warm. The more volume, the more capacity to hold it. And I'm surprised that you lost any since we had a very nice thaw come January and since. I'm seriously curious to know the depth and gallonage, to know the size of your fish in relation, as I think this had an effect.

I used an aerator for the first three years until one winter, the line got pinched and the hole closed for about two weeks. Didn't have a massive fish kill and this was the winter we had like record lows for February where the average temps didn't get above 20 F the whole month. We had a big fish kill that year at the big natural pond down the road, and that was the main reason.

Edit; I see you posted the gallonage. This means your pond is an average of 1.4' deep, or not even 18". I'd say this is a problem unless you have one end deeper and one shallower. Even then, if the pond iced up all the way down at the shallow end, you have less volume to hold oxygen in the deep end.

 

[Tula]

You asked about my pond cover. First of all, I'll explain why I decided to try covering it.

The cover prevents much evaporation from occurring and evaporation / wind is a big factor in chilling the water...think steam off a cup of coffee, or getting out of a hot shower.

When I look under the cover, the pond is open, no ice.....only a small amount at the edge of one side, when it was frigid. With the pond surface open, there is a big surface area for gas exchange.

In addition to the surface being open, the air stones provide an additional disruption to the water's surface. The same is true of the Pond Breather. The deicer is the last resort, a passive device that keep a hole open, near an air stone if the weather is frigid.

My cover is unsightly, but effective, a simple lean to. I use 2 x 6 boards in 16 foot sections and place a pool solar cover over it. It's amazing to me to peek under the cover and see some plants still living and the fish more active then in years before I covered it.

 

[AngelaM]

I keep asking re gallonage and/or depth? Is this 20' x 10' actual surface area or liner dimensions when you got it? Is this pond sunk in the ground or elevated?

The pond has a 12" deep shelf or step then it quickly drops down to 4 1/2 feet deep. It's 2100 gallons which I found out when I used a gallon counter as I filled it. It is sunken in the ground and not raised which is why the snow drifted over it so badly. I had no debris from summer in it. I cleaned it out every day right up until winter.

 

[AngelaM]

My cover is unsightly, but effective, a simple lean to. I use 2 x 6 boards in 16 foot sections and place a pool solar cover over it. It's amazing to me to peek under the cover and see some plants still living and the fish more active then in years before I covered it.

Tula do you have any photos? My pond is out in the open so I do get a LOT of wind across it. I'm going to have to make a cover or put up some kind of snow fencing to prevent these huge drifts next year.

 

[brokensword]

AngelaM;

if I assume this shelf goes all the way around, your dimensions approximate to 18' x 8' x 4.5' in the center. Forgetting the gallonage of the shelf area, your interior gallonage (deep part) becomes 4847. So, something is off even if I've rounded and assumed. Can you get more exact measurements of the deep area? The equation for calculating your gallonage is L x W x D x 7.48. Now, this obviously assumes a rectangular shape and constant depth. Still, 4847 is more than double what your gallon counter is showing. There's something off, here. Is your pond a liner or preform? Can you at least draw the basic shape and note approx measurements? And, is the drop off constant at 4.5' (other than the shelf area, which I would assume would freeze totally and the fish would not be up there). IF your deep portion is that deep and you have more than enough volume, it shouldn't be for lack of oxygen, esp since your fish are not that large for koi (though, they'll probably get there, eventually). Lack of oxygen is still a prime suspect; the idea is to figure out why and prevent future issues. Hard to see this happening if you have a large amount of water and adequate depth (as it seems you do).



Hmm, thinking further, provided the 4.5' depth is correct and the gallon counter is too, this would mean a surface area of about 62 sq ft, so something in the range of 6' x 10', give or take. Which seems a lot smaller than the afore mentioned 20 x10.

Still, a lot better than anything 18" or less, relative to depth. The larger the surface area, the more oxygenation occurs, though in winter and with only the one opening, I can't see how this becomes an issue, though volume of water would; the more you have, the more oxygen it's holding.

@MitchM ; do you have any further insight here?