Adivce Please

[PRW1988]

So last year my family moved to a beautiful new place, brand new. So I managed to convice my dad (which wasnt hard) to get a pond. The pond is 12' long X 10' wide X 6' deep. We had about a dozen small (5") Koi last year and unfortunatly the winter killed them. Now this year we've bought 6 larger koi (12"+) and my dad has decided he wants to try them in the pond over the winter again.

We had a heater last year but the location of the plug kept getting wet and the breaker would go off, this is my theory as to why the koi died. This year we've decided to add a bubbler as well as the heater, I'm changing the location of where the heater gets plugged in, in hopes of no more outtages. The heater will have the bubbler placed right below it at the end of the waterfall to maximize surface air exchange.


So, this is when I need the advice, I'm sure of my theory, but I'm not sure the fish will still survive. Also, I don't really know what to do when it comes to a final winter maintenance, can anybody give me some advice and/or tell me if my theory will work??

Thanks much.

 

[Ludwig Venter]

I'm thinking that something else went wrong.... Water freezes from the top down, and at 6' deep,.... I doubt if it'll get cold enough to freeze the top 1" of your water (in a 12'long).... I've kept Koi in much smaller and seen them frollicking below a frozen surface.... as it is with goldfish, they do tollerate a wide range of temps.

Maybe, with the heater in there, they did not acclimatise with the natural proggression of the season, so when the heater went down.... they were unacclimatised to the overnight change of temp and died.... (theory only)

I would not even put a heater in with Kois, putting them in early in summer and let them adapt to the natural seasonal change in temp.....

The bubbler will reduce the potential for the water freezing over, but I will brave it without a heater... (as I've done).

 

[Davo86]

Last year was an extremely harsh winter in the UK and a lot of pond fish didn't survive through it, however in this instance i would agree with Ludwig.

At 6 foot depth the pond should be more than capable of providing enough shelter for them throughout the winter and provided the filtration continued throughout on a pond of this size i can't see how there could be a complete wipeout of the fish,

Also even with the heaters, assuming they are the pond version, then i doubt that would have made too much of a difference to the temp, unlike aquarium heaters the pond versions will literally be just enough to stop a very small area from freezing, i.e. they are a freezing preventative, and in a pond that is roughly going to be 20,000L there will be very little change in temp overall IME, (unless you have a few dotted around)

Did you still feed over the winter by any chance? and also did the whole of the pond freeze over for a pro-longed period of time?

Also did all of the fish die in one go? you say the heater plug kept getting wet? I wonder if a wet electrical heater element could shock the fish?

 

[PRW1988]

I suppose I should've clarified what I meant by heater. The heater in question is a small, floating pond heater used to create a gap in the ice.

The power supply to the heater kicked out quiet often last year which is why I think the fish died as the hole wasn't always there.

I don't feed over winter as I know that the food can sit in either the Koi's stomach or the bottom of the pond, deteriorating causing damages to the fish and water quality.

Only thing I can think of other than the heater thing is that we never cleaned out the pond (leaves, twigs etc.), and their were a lot of frogs in it... Mabye they all died and that caused bad water quality killing the other fish?