Winter Kill

[Gino]

Hello all,

I am new member that just had a traumatic experience with my pond. I have a moderate size pond measuring about 15' round and about 40" deep with a waterfall. I have had this pond for 10 successful years. I have what I consider a double filtration with a skimmer and a media filter. Recently, I had some major loss of water and discovered that the top part of the skimmer had cracked from wear and from the surrounding foliage compressing the plastic and causing cracks. It was also advised that I replace the twin "Bio-Force" filters which I did and I replaced it with a single "Pro-Line" canister filter that has a back-flushing system. By the way, the skimmer that's on the main pond is still functioning but the upper system is now by-passed and the hose feeds directly into the upper pond.

In spite of some glitches I've shepherd this pond through the seasons with great success. My fish have happily survived through the extremes that we face in this part of the country. I have opened and closed this pond with little incident and no mortalities. But this year I asked the gentlemen that I contracted with solving the leaking issues to close the pond with me so I can see how to properly back flush the new filter. The first issue we encountered was that the pump attached to the new filter finally gave out. We decided that we can deal with that in the spring. He recommended that I treat the pond with salt and stress coat. I've done salt treatments in the past but never anything else except "Micro-Lift." So, I allowed him to administer the treatment.

In the last 8 years I have placed water heaters and bubblers in the pond but never had the need to run these except for the first 2 years when I became convinced by the health of my fish, that by just bypassing the filter and running the pump I maintain an opening for the gases to escape. I decided to follow the same ritual. The only difference is that I kept the skimmer running since the other pump wasn't functioning.

Now, we've had a couple of rough days right after Christmas with light snow falls and cold temperatures but the pond didn't freeze over completely and the pump was accomplishing the objective of maintaining a fluid area. But, just before we experienced the "polar vortex," I noticed a couple of fish "bellying up." I poked them and they seemed to regain their "consciousness." but I can see below that things weren't looking good. A couple of days later I started to see that I had dead fish. Since I had a business trip I texted the pond person and asked him to stop by and take a look. He texted me back and wanted to know why the bubbler wasn't running. I explained what I mentioned above. He said that he ran a test and said that ammonia was high and that methane contributed to their demise.

Well, the conclusion is I just skimmed out all of the dead fish and I don't think I have even one left out of close to 30 that populated my pond. After this long introduction, and I apologize for the boring narrative, what do you think was the "real" cause and what should I do to re-introduce fish back into the pond.

Thanks,

Lou

 

[DrCase]

Welcome to the Forum

If your ammonia was high that could do it

 

[tenchi]

If the ammonia is high, then I suspect there are more dead fish. Sometimes they die and don't float to the surface in cold water temps. Hi methane and ammonia leads me to believe there is an anaerobic condition. If the bubbler isn't working then the pond isn't blowing off the ammonia and methane fast enough.I don't know what to suggest other than a 50% water change. And get something to aerate the pond.
Have you been feeding the fish? What were the lowest temps? What is the pH?

Tenchi

 

[Gino]

Hi Gentlemen,

I understand the diagnosis but I'm perplexed at the cause since I haven't changed the ritual in all these years. Can you elaborate on your comment about it being anaerobic. Also, what do you suggest I do to prepare the pond for re-introduction of fish. By the way, I haven't been feeding them and I do have an aerator. When you ask about the lowest temps are you referring to ambient?

 

[tenchi]

Well, that is perplexing. I assume your pond is in the ground. Something has happened suddenly to elevate the ammonia levels. Until the source is found, I think the problem will continue. What was the lowest water temp reached and what was the pH, if you can measure it. Can you see to the bottom? Is the water cloudy?

 

[Gino]

Hi Tenchi,

The pond is in the ground. I haven't taken a pH reading yet. I honestly don't know what the lowest temperature except to say that this occurred just before we experienced the deep freeze which affected me the same as it did you. The water is clear and I can see the bottom. I do want to reiterate that although I had the aerator in the pond I didn't have it on.

 

[bettasngoldfish]

Anaerobic conditions can occur when there is a lack of oxygen and when a pond has lots of leaves or other organic matter on the bottom.

 

[tenchi]

Is there anything dead at the bottom of the pond? Sere if you can get a pH reading. I don't have enuf data yet to make a guess.
T

 

[DrCase]

How big were the 30 fish ?

 

[Mmathis]

Welcome, but sorry about your fish.

 

[mtpond]

Welcome! Sorry for your loss.

 

[Dave 54]

There is a condition known as sleeping sickness amongst fish where they become afflicted by the cold , they are normally found lying around the bottom of the pond as if they are dead, when proded they regain momentom but soon go bck down again.
If nothing is done at ths stage i;e raisning the water temperature by a few degrees they simply then pass away.
However here we continue throughout the winter our polycarbonate covering keeping the worst of the weather at bay and in all the years weve been outside weve nver turned our filters once.
He may well be right in what he says but then again if it got down cold enough prior to the Polar Vortex sleeping sickness could have claimed them

Dave

 

[shakaho]

If there is methane in the pond, there has to be a lot of organic material that is decomposing in the bottom in the absence of oxygen. Is there a layer of leaves and other debris in the bottom? Are there rocks on the bottom? Or is there a layer of organic debris over a layer of rocks?

First, I suggest you test your water for ammonia, nitrite, nitrate, and pH, so we know a little more about the problem.

Once it's warm enough for this to be a bearable activity, you should do a complete pond clean out. Get all of the debris out of the pond, remove any rocks from the bottom and pressure wash them (if you want to return them to the pond or use them elsewhere). Change all of the water, and rinse the bottom of the pond. Don't scrub the liner.

Once you have the pond running again, use that aerator to help prevent anaerobic conditions from building up again.

The coldest conditions you can get in your pond is when you have open water that receives a lot of frozen precipitation. The worst situation is one in which the whole pond becomes slushy, which means that all of the water is at 32F. In an iced-over pond, the liquid water deep in the pond never gets that cold.

Your fish could have been zapped by a combination of toxic conditions and extreme cold.

 

[dieselplower]

Salting the pond for Winter could allow the water temperatures to go below normal freezing temps. It does sound like a nasty combo of events. I also want to point out that running an aerator will not help lower ammonia levels, since ammonia is not a gas.

 

[Gino]

You have all been very helpful and generous with your input. I found the suggestion of "sleeping sickness" to be intriquing because, after research the subject, I found that the behavior was very similar as the description. Altough I see similarities I also noticed that it seems to strike frys and smaller fish more pervasively. But, I can't seem to explain why I lost my larger fish to this condition. Frankly, after reading your observations, I think there were a number of factors thhat lead to this phenomena. And, I thiink that temperatuure along with not having the bubbler running may have played a big role. I've since moved on. Yesterday, with the January thaw, I had the occasion of removing the remains and haven't seen any survivors. I was instructed to keep the bubbler on in case there were any that might be hiding in the recesses and avoid having the water to stagnate. It was also advised that add a preparation, whose name escapes me, that will decompose any organic debris such as leaves and to wait untill spring to do any water treatment and repopulation of the pond. For now, I sit and ponder: "what if."