Holding tank

[Lisak1]

People always ask us "how cold does the water get?" and I'm like "well, cold enough for the top to freeze!" haha!

 

[MitchM]

Cold enough for water to freeze.
Yep.

 

[sissy]

I have one but since pond is so close to the septic tank water at the lowest rarely gets below 45 degrees .I wish they marked the thing because I have no clue the brand and I got it as a gift .I put it about 6 inch's off the bottom .The unit I read indoors got the name rubbed off of it from touching it .If I can remember it is around 6 years old .The newer ones are probably much better .Not sure of how accurate it is .When we cleaned out the closets I think the book got lost in the mess .

 

[carolinaguy]

Sorry, but that's incorrect. koi do fine down to 32F, for months at a time.

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Actually it isn’t incorrect. The only marine animals able to survive 32 degree water are in Antarctica and have blood antifreeze to avoid ice crystal formation. At 32 degrees, water loses a huge spike in energy as the crystals form and parts of the water are crystalline while some are not. These crystals puncture tissue and destroy cells. At 34 degrees there is enough of an energy cushion that the crystals cannot form. From the aquaculture community you will find that they avoid approaching freezing for this precise reason.

That said, if we don’t have thermometers at the bottom of the pond how do we know what that temperature is, and how can we say that koi do fine at depth temperatures of 32 degrees? The literature says otherwise and so does the physics.

 

[MitchM]

Marine animals don't enter into the equation here.
Some of us do have accurate thermometers at varying depths within our ponds.
Our ponds have various salts and impurities in the water so can actually reach temperatures below 32F. Water circulation will also prevent freezing, to a degree.
Some carp have been shown to be physiologically adapted to survive in cold temperatures by converting lactic acid into ethanol. This adaptability also helps them survive longer in a low or zero oxygen environment.

If you have some literature that demonstrates that koi will indeed die at 33F, please post it.

Otherwise, we here that have kept or are keeping koi in 32F water will continue to do so and not inform the koi that they should be dead.
We have one member here that has been keeping the same koi through our 6 month winters for more than 20 years.

.

 

[carolinaguy]

And of course you know the temperature of your pond at depth because it’s not the same as at the surface.

 

[MitchM]

And of course you know the temperature of your pond at depth because it’s not the same as at the surface.

I know the temperatures because I had separate temperature probes at varying depths.

You made a definitive statement that koi will die at a certain temperature, so I'm asking where you got that information from, because it goes against everything I have learned and if people follow your belief, it could lead them to try find solutions to a problem that doesn't exist.

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[carolinaguy]

Okay. Just google koi temperature range or phrase that captures the concept of the lowest temperature for koi. Spoiler alert. The range for long term koi husbandry bottoms out at 34 degrees. One article states that ice crystals form in the gill tissue and kills the fish over time. The physiology will also be mentioned stating that koi are poikilothermic which means that their body temperature adapts to the temperature of their surroundings. In summer a koi body temperature is about 2 degrees higher than the surrounding water. In winter the koi metabolism slows and their temperature approaches the surrounding water. And it would be great if you could document that koi generate ethyl alcohol in their blood. That would be great to share with the koi world. Koi are related to yeast? Wow.

 

[MitchM]

(I posted these on this forum last year for discussion)

Here is the peer reviewed study:
https://www.nature.com/articles/s41598-017-07385-4

and the layman's version:
https://www.sciencedaily.com/releases/2017/08/170811085036.htm

I would still appreciate it if you could post which article you are using for reference.

.

 

[carolinaguy]

That’s why they call it google. I’m still trying to find the ethyl alcohol koi article. I’ll keep trying. Why don’t you share pictures of your temperature measurement system at all levels of your pond. Sounds great.

 

[MitchM]

Ok, so you can't provide an article. Just say so. It's most likely an old article.
The study I posted above is recent and done on a species of the Cyprinidae family.
The Cyprinidae family includes carp and minnows.
Everything I've seen with regards to how healthy goldfish, koi and minnows survive winter conditions, tells me that they all most likely possess the gene that allows them to survive cold water, below 34F.
I have yet to see any fish deaths of koi, goldfish or minnows that can be attributed to cold temperatures.
Deaths have been caused because of weak fish going into winter or poor water conditions during periods of ice cover.
Because of how recent the study was done, plus your comment about yeast tells me that you may not have been previously aware of this article.
If you have a different explanation how koi are presently surviving temperatures below 34F (because they are), please elaborate.

.

 

[carolinaguy]

You do know what google means don’t you? Plenty of material out there. The articles are crying for you to push the button. You do understand the laws of physics, right? And in the mean time if someone follows your advice and keeps Koi in 32 degree water long term, are you willing to reimburse them for the loss? It’s easy to be an anonymous, distant internet expert. It’s easy to believe. Good luck with that.

 

[MitchM]

Forums such as this one exist to help people with quality and relevant information so they don’t have to decipher all the nonsense that’s available on the internet.
Telling someone to “google it” when asked for data backing up a claim helps no one.

 

[addy1]

I just googled it.............per the net koi and goldfish die below 50F and also survive down to almost freezing water as long as they are not frozen in the ice.

Take your pick!

 

[Mucky_Waters]

I "Googled" it and this is one article I came up with. https://www.pondexperts.ca/pond-advice-tips/how-to-winterize-your-pond/
To quote " Goldfish and koi are very hardy fishes; they can survive water temperatures as low as 0°C, which means they can survive in the pond during the winter as long as it doesn’t freeze solid and they have adequate water quality and oxygen."
I will admit there are plenty of articles that state a much higher minimum temperature should be maintained for Koi, but personal experience has taught me that koi are not harmed by near-freezing temperatures providing they are healthy and other water parameters are kept in check.

Opps, I see Addy just jumped in there and beat me to the punch with a similar comment.