Val and I are in total shock.

[Lisak1]

So people no more arguing it will scare off folks from asking for answers of the forum , which in our view is one of the best around...

I don't think anyone needs to consider it arguing @Dave 54 - somehow we seem to have lost the ability to debate and share varied opinions without people taking it personally. We can all learn from the discourse, is how I view it. I learn so much from people who understand HOW things work vs myself who just muddles through and feels lucky when my method is successful. It's a good feeling to have that light bulb go on and go "ahhhhh! So THAT'S the answer!" And admittedly sometimes I have to re-think my own conclusions and see how they jibe with the facts that are presented. It can be an exercise in humility.

One thing I've often wondered about is the disagreement between whether koi are cold water fish or warm water fish. The conclusion I've reached - and feel free to tell me if I'm wrong - is that this is an aquarium definition. Koi do well in unheated tanks (thus "cold water fish") unlike tropical fish which require heated tanks. Koi have adapted to cold water, but that doesn't make them cold water fish. To use the trout example, a quick google search tells me that trout begin to suffer if the water temperatures go above 66F (this temperature can vary by actual species). If koi were true cold water fish, they would love our cold winter ponds but wouldn't tolerate the times when our ponds go above 70 degrees F - which in my case is pretty much from May through September.

 

[callingcolleen1]

@adavisus Agreed koi are in acctual fact semi tropical in their origins also you have to remember @callingcolleen1 that Chinese and Japanese winters differ from our own in they are sharp but short unlike our own..
All of the koi dealerships are known for bringing in their koi for the winter months. .
There is one voice i know that shouts it out from the rafters every chance he can get "Peter Waddington" Author of Koi Kichi , koi2kishi and many other books .
He recommends we should indeed heat our koi if we are leaving them outdoors going so far as to callit cruel to leave them in unheated ponds .
For those of you who dont know , these two books are considered amongst the very best ever written on the subject of koi ..
As to Parasites my koi are free of them and are scraped religiously once every year,,
Besides that@callingcolleen1 at these temperatures parasites are still in the land of nod and as such are inactive ......
We do cut the feed down to winter levels using only pellets made for temperatures of 5c and slightly bellow only on a two week basis .


Dave 54

I don't ever get parasites, and yours may be dormate but they can weaken your fish and that could lead to death when stressed, such as in freak winter storm you experienced.
No such thing as semi- tropical fish.... In the Oxford Concise Dictionary. Just Tropical or cold water. If my koi were Semi-tropical they would surely not survive -50 below weather after 27 years in my ponds all winter.

Dave have you never seen my video's?

 

[callingcolleen1]

I don't think anyone needs to consider it arguing @Dave 54 - somehow we seem to have lost the ability to debate and share varied opinions without people taking it personally. We can all learn from the discourse, is how I view it. I learn so much from people who understand HOW things work vs myself who just muddles through and feels lucky when my method is successful. It's a good feeling to have that light bulb go on and go "ahhhhh! So THAT'S the answer!" And admittedly sometimes I have to re-think my own conclusions and see how they jibe with the facts that are presented. It can be an exercise in humility.

One thing I've often wondered about is the disagreement between whether koi are cold water fish or warm water fish. The conclusion I've reached - and feel free to tell me if I'm wrong - is that this is an aquarium definition. Koi do well in unheated tanks (thus "cold water fish") unlike tropical fish which require heated tanks. Koi have adapted to cold water, but that doesn't make them cold water fish. To use the trout example, a quick google search tells me that trout begin to suffer if the water temperatures go above 66F (this temperature can vary by actual species). If koi were true cold water fish, they would love our cold winter ponds but wouldn't tolerate the times when our ponds go above 70 degrees F - which in my case is pretty much from May through September.

thats why koi have so many parasites down south and in England. You should check out some of the U tube channels from the UK. They are always dealing with all kinds of parasites and disease. Its actually quite shocking to me as my koi are so healthly winter after extra long winter here in ice cold Canada.
Also no such thing as Semi Tropical fish. Also next to no koi ponds in the tropics. In Cuba I could not find one koi pond.

 

[Tula]

Speaking only for the koi, in my pond. If activity and eating are behaviors seen as positive, my koi prefer warmer water over cold water.

 

[callingcolleen1]

@adavisus Agreed koi are in acctual fact semi tropical in their origins also you have to remember @callingcolleen1 that Chinese and Japanese winters differ from our own in they are sharp but short unlike our own..
All of the koi dealerships are known for bringing in their koi for the winter months. .
There is one voice i know that shouts it out from the rafters every chance he can get "Peter Waddington" Author of Koi Kichi , koi2kishi and many other books .
He recommends we should indeed heat our koi if we are leaving them outdoors going so far as to callit cruel to leave them in unheated ponds .
For those of you who dont know , these two books are considered amongst the very best ever written on the subject of koi ..
As to Parasites my koi are free of them and are scraped religiously once every year,,
Besides that@callingcolleen1 at these temperatures parasites are still in the land of nod and as such are inactive ......
We do cut the feed down to winter levels using only pellets made for temperatures of 5c and slightly bellow only on a two week basis .


Dave 54

I will look up that peter Wellington and set him straight. He obviously does not know nothing about wintering koi either. Just because he has a book does not mean he knows everything. Its obvious he knows very little about wintering koi. Book must be out of date too...

 

[adavisus]

You can find Waddy on facebook. You put him straight eh. Would you like a link. He is quite the gent and very amenable to be given what for.

https://m.facebook.com/peter.waddington.33/about

It is a temperature thing, the diff between a steady winter in torpor in a big pond has different hazards to a stressed pond where seven months out of the year, fish are vulnerable in borderline conditions and any parasite or disease can turn up on the back of a duck or frog, from a local pond or stream

A particularly tacky hazard is herons turning up at dawn, any time in Winter, puking the remnants of the last pond as a tasty bait to tempt fish out from cover...

And lets not mention otters or mink

 

[Mucky_Waters]

Pump colder than freezing air into the bottom of a pond and crystals form, swirl into the water, besides crashing the thermocline of dense, and cold water. Fish gills suck those crystals into their gills, 24/7 and choke

Koi are warm water fish, hibridised over centuries in warm chinese and Japanese waters in Summer Erratic or prolonged cold freezing winters are difficult for them unless they have large, deep, still water

Not sure what you mean by "warm water fish", but Koi are definitely not tropical fish. Yes, they can survive in warm "tropical" water but by all standard definitions, they are true cold water fish, in that they generally do better in water that is cooler than tropical temps, and they can survive fairly long periods of near-freezing temperatures in which no "warm water" tropical fish could ever endure, for any length of time.

Also, where are you getting that information about aeration? It seems to me that if what you are saying about ice crystals forming on the gills of fish was a legitimate issue with aeration then all the money the fisheries departments are spending on aerators trying to keep fish alive through the winter would be wasted, and rather than preventing millions of fish from succumbing to winter fish kills they would be causing it. I'd sure like to see some sort of documentation on the subject.

 

[adavisus]

Koi are hibridised carp, from climates with hot summers, cold winters. Not much temperate about them for long. Winter slams in, hot summers chase them away. Waters in the 70-95f range

Fisheries operate on a large scale, an aerator is probably going to be positioned mid depth, to avoid stirring up deeper waters. The hazard of super cooling water at the wrong time is a topic. Feel free to look the topic up on pondboss.com. Opinions will vary between fish farming in hot and cold climates, and be heavily influenced by folk peddling devices that squish water about

 

[BarbO]

A particularly tacky hazard is herons turning up at dawn, any time in Winter, puking the remnants of the last pond as a tasty bait to tempt fish out from cover...

In this whole sad and disturbing thread I find the above hazard to be the most horrifying. Do herons really do this? I am rethinking even adding shubunkins to my new small pond. Herons abound here. So much to concern us pond keepers.

 

[adavisus]

When rivers, lakes are frozen over or clouded by storms, herons go looking for the bright colours of perty sushi bars. A net over a pond in the Winter months and a host of other cunning methods can foil such foul fowl

Heron pie was a popular feature in ye olde english tavern,,, Folk would put a fishing net across a pond with a tiny gap, wait at dawn for the sneaky heron to sneak in the narrow gap, shout 'boo' and the silly bird would crash its mangey wings into the net, sure to meet with a quick fate at the hands of umpteen medieval instruments

Nothing sad or disturbing about a poultry pie

Going for the daily stroll around the ponds here, who knows what will stir, large owls, eagles, herons...

 

[Lisak1]

Do herons really do this?

They are sly, patient, and experienced hunters. We have lots of them in all the natural ponds around us. They fly overhead many times per day. Our yard is fenced in and doesn't have a good in-and-out for them with the tree cover, so they've stayed away so far. But last year we did watch a snowy egret sit in the very tip top of our neighbor's tree that overlooks our yard for an entire day, as still as can be for hours. He/she finally left and hasn't been back, thankfully. And yes, they will regurgitate into the pond to simulate food falling in to lure the fish to the surface. Quite brilliant when you think about it.

 

[Mucky_Waters]

Koi are hibridised carp, from climates with hot summers, cold winters. Not much temperate about them for long. Winter slams in, hot summers chase them away. Waters in the 70-95f range

Fisheries operate on a large scale, an aerator is probably going to be positioned mid depth, to avoid stirring up deeper waters. The hazard of super cooling water at the wrong time is a topic. Feel free to look the topic up on pondboss.com. Opinions will vary between fish farming in hot and cold climates, and be heavily influenced by folk peddling devices that squish water about

A lot of words, but not much of it makes much sense.
I live in an area with hot summers and cold winters, the native fish in the local lakes include Carp, Trout, Kokanee and plenty of other cold water fish. Koi released into the wild here do quite well and can live long healthy lives. No species of tropical (warm water) fish can survive the winters here.
There is really nothing more to say about that.

As far as aeration goes, most aerators the fisheries set up are set up to deliberately disrupt the stratification (Destratification) in lakes and ponds to provide oxygen to the lower levels and help prevent anoxic conditions which lead to winterkill of fish.
Since you can't provide any specific references for me I will provide one for you, read this > Lake aeration in British Columbia: Applications and experiences This is based on real-world applications and data, no peddlers selling stuff or second party conjecture.

Here is a small snippet from the research data.
"Artificial circulation is now standard practice on 18 winterkill lakes (mean depth 2.0 to 17.4 m, surface area
3.2 to 41.3 ha) in the Southern Interior region (Table 2). All of the current artificial
circulation installations are destratification systems, although the first hypolimnetic
aeration system in Canada was operated on Black Lake (near Penticton) from 1978
to 1981"

 

[adavisus]

There's a bit of a diff between ponds 17 metres deep that pile up deep layers of methane and hydrogen sulphide just waiting to erupt when waters invert and koi or garden ponds, which are not usually 2m deep

Feel free to look up the subject, direct from the source. Pondboss.com

 

[Mucky_Waters]

There's a bit of a diff between ponds 17 metres deep that pile up deep layers of methane and hydrogen sulphide just waiting to erupt when waters invert and koi or garden ponds, which are not usually 2m deep

Water, ice, oxygen, aeration, stratification, fish,,,, there are more similarities than differences and it's precisely because of their relatively small size that they generally need aeration. It's certainly on topic and more importantly, it strongly disagrees with what you were saying about fisheries wanting to avoid "stirring up the deeper waters".
Anyway, it is the kind of data that can be supported and it's the sort of data that I would like to see before I'd put any stock into any theory about supercooling and ice crystals forming on fish gills because of aeration. Which coincidentally, there is no mention of in that report.
It's certainly true that prolonged periods of near-freezing temperatures can be detrimental to Koi and weaken their immunity, however this is true of many other cold water species of fish that live in temperate zones not just koi, The main killer of fish in small ponds (no matter the size) and lakes though is the anoxic and toxic conditions that develop because of a lack of water circulation and oxygen mixing. That can even happen in the summertime, but if it happens in the winter under the ice when the fish immunity is lowest you are more likely to end up with a lot of dead fish.

Interestingly but not as relevant to the conversation, just a couple miles from my house is one of the lakes mentioned in that report (yellow Lake), they run a deep compressed air aerator every winter. That small lake supports a lot of fish, it is a favorite for anglers because of it's easy access, it's right on the highway. They stock it with new young trout and kokanee ever year and they grow fast because of the abundance of natural food in the lake. The only problem is without aeration the lake suffers from regular fish kill so they must aerate it through the winter to maintain the fish stocks. I mention it because many people have spotted ornamental koi that live in there. Probably not what the fisheries want, but unless somebody catches them they will probably be there for some time.

 

[adavisus]

No, you don't want to stir up waters below ice layers, where it's going to break up the stratified 40f stable water and can kick up lethal doses of methane and hydrogen sulphide deposited in larger natural ponds