Simply Koi and More Koi

Hi everyone,

I've just got the well overdue digital heater to replace the old analogue one and it got me to wondering what temperature I should be setting it to over the colder months.
I've had a lot of conflicting advice over the last few years with the majority of "heaters" recommending temps of between 9 and 13 degrees as well as those who say I should keep it as warm as I can afford to!!
What temperature do others aim to keep their ponds at, and why? I'm particularly interested in getting a definitive answer to the temperature that I need to stick to in order to avoid the slowing down of the immune system. I didn't heat over this last winter and wished I had, since I experienced several problems as the "nasties" seemed to get active before the koi's defence systems had fully kicked back in.
Thanks in advance,
Louie

Hi there,

For my main pond through the winter we normally try and heat to 12 degrees. I was always told that was good for their immune system. But with the weather being as rough as it has been the last two winters and having to heat my baby tank last year. I ran it to 12d and then dropped it to 8.

The baby tank, I kept at 15d.

I guess it is a case of what you can afford.

The first year we heated, I had chilodonella and had to raise the temp as high as I could. It subsequently cost us a fortune.

Now we've off set our heating costs with solar panels And don't have to worry over cost now.

Hope this helps. Also interested in what others do myself.

Well....That was a waste of time, wasn't it!

I had a 3kw heater fitted this year and was advised that the temperature through the winter should be 8c. We had quite a lengthy discussion at one of our koi club meetings about heating and 8c seemed to be the norm.

I usually heated to 13 but last year I followed advice from various forums and took it down to 9. I won't be doing it again as one or two fish were not happy with it and took a long time to perk up when raising the temps and were fairly weak coming out of winter and most had some indication of slight carp pox. I will take it to 12 this winter to keep them all happy. The only ones that did not seem to mind the lower temp was the ones I have over 4 years old. I also chatted about it at my club and some that are very experienced Koi keepers said they usually heated to 14 but due to energy prices were taking theirs down to 8 last winter and their fish were not happy at all so they increased it after a few weeks to 13. It is only a few degrees but it must be quite a lot to a fish. Also cover with Polycarb and it will not burn to much power.

That sounds a lot like my experiences. I know it's pricey but 12 or 13 degrees is what I'm likely to stick to from now on.