I'm so upset! Two dead Koi! l

[Tula]

I have to chuckle reading Michael's post, as it pretty much describes me...throwing everything but the kitchen sink at my pond for the winter - ha ha!

I've read here many times that aerators do NOT add O2 to water. Is there anything that does? Or does it increase O2 due to the disturbance at the water's surface.

 

[MitchM]

I agree with everyone saying it's a good idea to have some redundancy when it comes to making sure you provide good gas exchange during ice cover.

At this point, I'm wondering if the koi were exposed to a high level of ammonia between the time that they were moved from the original owner to the time you had a mature biofilm that could properly process the waste they produce.
In that case, the koi's gills could have become damaged (not reversible) and they just happened to die while you had ice cover. No amount of gas exchange would have prevented their deaths.
My concern now would be that the other surviving koi also have gill damage so you would be best to ensure you have the best water quality possible from here on.

For the record, pond breathers are not designed to reduce ice cover, they are designed to provide gas exchange.

.

 

[Lisak1]

I'm wondering if the koi were exposed to a high level of ammonia between the time that they were moved from the original owner to the time you had a mature biofilm that could properly process the waste they produce.

That kind of lines up with my thought - something happened (or a series of things even) prior to winter and the cold became just the final straw. Knowing the condition of the remaining fish would definitely be helpful.

 

[brokensword]

I have to chuckle reading Michael's post, as it pretty much describes me...throwing everything but the kitchen sink at my pond for the winter - ha ha!

I've read here many times that aerators do NOT add O2 to water. Is there anything that does? Or does it increase O2 due to the disturbance at the water's surface.

Yeppa, Tula, that's the idea. I know I grew up with the myth/idea that the bubbles going up my aquarium wall provided the aeration. It wasn't until Meyer showed through the science that very little (almost immeasurable) O2 is transferred to the water column this way. Because you have agitation at the surface, you have much more contact and surface area for the water and air to interact. Hence, you need turbulence to help with aeration. Otherwise, you need a really large surface area to make up for that (or waterfall, stream, etc), that's why inland lakes and ponds don't need aerators. Still, they DO experience fish kills sometimes, when the above factors collide. Thankfully, it doesn't happen very often to our natural ponds and lakes.

Glad you chuckled!

Michael

 

[AngelaM]

A mature biofilm takes 4 to 6 weeks to develop after an ammonia source is added.
What size was the stock tank and how many fish were kept in it?

It was a 100 gallon stock tank with 5 fish in it.

 

[AngelaM]

https://m.drsfostersmith.com/product/prod_display.cfm?pcatid=14444

So would this work for winter months? Then I'll get the round Matala for the rest of the year.

 

[MitchM]

It was a 100 gallon stock tank with 5 fish in it.

Yes, I think that could be the problem. That many large fish in a small container could get some high ammonia readings in a short amount of time.
In addition to the GH/KH test kit, I would also purchase a dissolved oxygen kit and observe the measurements over the year at different times and temperatures. Make notes about how much algae there is at the same time.
https://www.marinedepot.com/Salifer...ter_Aquariums-Salifert-SF1131-FITKSI-vi.html#

You'll need a more substantial air pump than the one in the link you posted.
Make sure you choose a pump that is rated for proper depth and use weighted hose.

 

[addy1]

I quit using a aerator in the winter when a neighbor/friend lost every fish one winter using one. Had nice open water, dead floating fish. Best guess, super chilled the water. Large pond now filled in.

I only use the pond breather now for the last 4 years, never have any floating fish.

 

[sissy]

I guess it comes down to what old man winter throws at you for winter weather .I don't really get harsh winters here except for the 2 weeks last year and made records here .I was also amazed that your fish being 10 years old were only a foot long as mine are well over 2 feet long .Could they be a mixture of other fish .I know mine are mutts so maybe hardier .I keep all my air stones at different heights ,but then again I do not get as cold here in the winter .I am not sure i could take those cold temps .anymore .I just know when it comes to winter I always prepare for the worst and hope for the best .I know up north right now it is severe and hope the best for every one in the line of Riley .

 

[MitchM]

I don't think this had anything to do with winter but had everything to do with fish being exposed to high ammonia levels, which can happen anytime fish are moved from one environment to another.

 

[sissy]

I have moved my fish several times .4 times in total and last 2 times they were over 2 feet long and as long as you filter water and test it they can be fine .Was really 5 times if you consider the first pond was just preformed until the front porch was finished but then they were tiny .2 dogs and moles destroyed my other liners .I thought about taking stock out in pond liners .So it depends on precautions made before you move fish and using as much of the original pond water as possible .At least I had well water so it made it a little easier

 

[Lisak1]

It was a 100 gallon stock tank with 5 fish in it.

I'd put my money on that being the tipping point. Too many fish is too little water for a protracted period of time. And then a too new pond. And then winter.

My scientist son likes to remind me that "correlation does not imply causation". In other words, the fact that the previous pond owner ONLY used an aerator and the fish did NOT die, does not mean the aerator would have changed this outcome. Likewise the fact that you chose to use a pond breather and the fish DID die does not mean the pond breather is to blame. I don't use either one during our cold winters (nor do I use a cover or a cattle trough heater or a de-icer or, well... you get the point!) and my fish thrive. But it would be false reasoning to assume that my fish DON'T die because I don't employ any of those strategies.

Every pond is different, every season is different, every circumstance is different. Sometimes things can work for many many years and then suddenly one variation can tip the balance and the outcome is different. Even nature isn't perfect - fish kills happen in natural ponds and lakes due to NATURAL variations in circumstances. Trying to compare one pond to another is pointless. Each pond owner needs to consider their own set of circumstances and learn through observation (and sometimes, sadly, the hard way) what works for THEIR pond.

I remain curious to know how the remaining fish are faring. Any signs of them struggling now that you can observe them in the pond? I think that's an interesting factor - why SOME of the fish but not ALL of the fish.

 

[AngelaM]

I remain curious to know how the remaining fish are faring. Any signs of them struggling now that you can observe them in the pond? I think that's an interesting factor - why SOME of the fish but not ALL of the fish.

I'm assuming they're still alive. I haven't seen any of them yet. They're still hanging in the deep end and it's too dark to tell. I can't see to the bottom yet.

 

[Lisak1]

I can't see to the bottom yet

Why?

 

[AngelaM]

Why?

I don't know if it's that I can't see bottom or the fish just blend in too well. My two bright orange ones are the ones that died. I have the pure black molly, and black and white Koi so they blend with the liner pretty well. After I found the dead fish I cleaned about 6 nets of leaves off of the bottom so I stirred the water up a bit. It's a little murky right now. Should it be crystal clear right after the ice thaws? If so mine was not.