New pond owner. I need help.

[sissy]

If the pond is small could the trough heater be to big and over heated the water to fast and the lack of oxygen be made worse ? not sure but some trough heaters can get my 300 gallon stock tank way to warm and you can feel it is warm with my hand .Maybe should have gotten a deicer ..

 

[Meyer Jordan]

The pond is only filtered by the water fountain which is off now.

You may find that the lack of adequate biofiltration is the source of your fish mortalities.

 

[adavisus]

If the pond froze over with ice sealing the surface, a topping of snow on top, that blots out light for a week, you have a recipe for all the algae to die off in the darkened waters for lack of photosynthesis. It takes a couple of days for methane and hydrogen sulphide to build up to toxic levels beneath that sealed ice plate

Clearing snow snow off the ice to let light penetrate the ice and a small vent in the ice can avert such a stress....

 

[MitchM]

I do not advise clearing snow off of an ice covered pond if you do not know for sure that it can carry your weight.
Escaping from falling through the ice is extremely difficult.

 

[Meyer Jordan]

If the pond can be accessed from the safety of the perimeter, the removal of snow cover from even a small area will allow enough light to penetrate the water column to promote photosynthesis. There are many algae specie that respond quite well to low level light.

 

[MitchM]

All good advice.

 

[morewater]

Pond de-over wasn't the culprit. Most likely lack of O2 compounded with decaying debris.

 

[sissy]

It depends on what sized stock tank heater was used also .If it heated the water to much then it caused the problems twice over.Also could there have been an electric shock from it if defective

 

[carolinaguy]

I'm not a cold weather guy,but that said the previous suggestion about oxygenation might be correct if the surface was entirely ice covered AND there was no air gap below the ice between the ice and the water.

Koi are safe down to about 34 or 35 degrees If there is an ice cover, you are okay with a 4 foot depth. This is only a guess, so just take this with caution. Using a heater actually puts the fish in jeapoardy for two important reasons. First the water temp increase will make the fish more active and cause them to use more oxygen, hence the potential for oxygen depletion with an ice cap. The largest fish will die first in my experience. Second you have the potential to raise the water temp above 48 degrees which is the threshold for waking up harmful bacteria. The koi immune system doesn't kick in until about 65 degrees, so the aeromonas zone as it is sometimes called, between 48 and 65 degrees, puts koi at risk for infection. You are better off over the winter to be below 48 degrees. Sorry for your loss.

 

[Meyer Jordan]

48 degrees which is the threshold for waking up harmful bacteria.

Where might I find support documentation for this statement?

 

[carolinaguy]

Where might I find support documentation for this statement?

Any of the vet books. Check st earne or johnson

 

[carolinaguy]

Where might I find support documentation for this statement?

Lots of websites with this info. Google aeromonas alley.

 

[Meyer Jordan]

Lots of websites with this info. Google aeromonas alley.

Your statement indicated "harmful bacteria". I am well familiar with Aeromonas, but I was looking for documentation that this stated temperature applied to all pathogenic bacteria as you indicated. Aeromonas were not specifically mentioned.

 

[carolinaguy]

Aeromonas alley is a colloquialism used in the hobby to describe the temperature window between 48 and 65 degrees where koi are the most suseptible to pathogenic infection and cannot use their immune system to defend themselves. The fish are attacked by a classic parasite in these temperatures like a fluke which penetrates the skin or gill surface and then opportunistic bacteria like pseudomonas or aeromonas enter the fish body and eventually cause sepsis and pine coning. It's a dangerous world out there.

 

[carolinaguy]

Your statement indicated "harmful bacteria". I am well familiar with Aeromonas, but I was looking for documentation that this stated temperature applied to all pathogenic bacteria as you indicated. Aeromonas were not specifically mentioned.

Well you don't need a temperature where all pathogens grow. You only need one pathogen to kill your fish. Why the hair splitting? Feeding below 50 degrees is just bad koi husbandry. I wouldn't encourage a new guy to feed early. Why?