Fish dying as water is turning colder

[WaterGardener]

With a pond that size, I would think there would be very little change in the temperature of the water, even with that big a swing in air temp. What is your current water temperature?

I, too, am suspicious of your KH, that it is too low. I keep mine around 200ppm. My filters work best at that level. KH is easily raised with plain old baking soda. You can get large bags at big box stores like Costco for a good price.

A higher KH will keep your pH stable. It can raise your pH to around 8.2 or so, but that is no problem. Keeping it stable is the important part, and if it is bouncing around, it will stress the fish. If it isn't addressed the pH can crash, making the water acid and killing the fish and your beneficial bacteria.

I do know of some people that have to bring their koi inside for winter, as some of their fish just can't tolerate the cold water. I really don't think that is the issue here, especially with that amount of water. Others cover their pond with a greenhouse type structure to keep it from freezing. We do that and the water temperature never drops below 45 degrees, even with single digits and feet of snow outside. It keeps the wind off the pond, which creates evaporation that cools the water, and it holds in the warmth from the water and the ground. It works amazingly well.

For now I would address the KH and bring that up. You will need to periodically dose it since it gets used up with the nitrogen cycle, so it needs to be tested once in a while.

 

[12cats]

Agree with @Lisak1 and others — salt isn’t the answer....and we need more information about your pond.

I haven’t read carefully through all of the replies, so I hope I’m not asking what’s already been addressed. But, where do you live, how deep is your pond, how many (total) fish do you have, including their approximate sizes?

Yes in a previous reply I answered your questions. Would it hurt to put in melafix as a precaution?

 

[WaterGardener]

Melafix does nothing. There was a recent study proving that and I will see if I can find that. Also, since it's an oil, it doesn't mix well with the water and it can actually coat the gills of the fish and make it more difficult for them to breathe. The last thing you want with an already compromised fish is to stress them more with something you put in the water.

Always fix the water first and you water is low on KH. Correct that before you add any kind of "medication" to the water.

 

[12cats]

With a pond that size, I would think there would be very little change in the temperature of the water, even with that big a swing in air temp. What is your current water temperature?

I, too, am suspicious of your KH, that it is too low. I keep mine around 200ppm. My filters work best at that level. KH is easily raised with plain old baking soda. You can get large bags at big box stores like Costco for a good price.

A higher KH will keep your pH stable. It can raise your pH to around 8.2 or so, but that is no problem. Keeping it stable is the important part, and if it is bouncing around, it will stress the fish. If it isn't addressed the pH can crash, making the water acid and killing the fish and your beneficial bacteria.

I do know of some people that have to bring their koi inside for winter, as some of their fish just can't tolerate the cold water. I really don't think that is the issue here, especially with that amount of water. Others cover their pond with a greenhouse type structure to keep it from freezing. We do that and the water temperature never drops below 45 degrees, even with single digits and feet of snow outside. It keeps the wind off the pond, which creates evaporation that cools the water, and it holds in the warmth from the water and the ground. It works amazingly well.

For now I would address the KH and bring that up. You will need to periodically dose it since it gets used up with the nitrogen cycle, so it needs to be tested once in a while.

I have ordered some baking soda and have already put on a solar cover. A cheap one but I'm hoping it helps. Water temp last night was. 43, it has been in the mid fortys for a few days. It seems like the warm up helped. It is impossible for me to get to the fish and it looks like most of the ones that were lying on their sides have died. Would it hurt to put melafix in as a precaution?

 

[12cats]

Melafix does nothing. There was a recent study proving that and I will see if I can find that. Also, since it's an oil, it doesn't mix well with the water and it can actually coat the gills of the fish and make it more difficult for them to breathe. The last thing you want with an already compromised fish is to stress them more with something you put in the water.

Always fix the water first and you water is low on KH. Correct that before you add any kind of "medication" to the water.

Thanks for your advice.The baking soda should be here tomorrow.

 

[mrsclem]

Totally disagree with opinion on Melafix. Just my opinion but several years ago I had a water quality issue with one of my ponds that resulted in sever bacterial infections and fin rot with my koi. Used Melafix and followed up with Pimafix and while I did lose some koi, most totally recovered.

 

[WaterGardener]

Do you have a sinking thermometer so you can see what the water temperature is at depth? I suspect it is warmer 6 feet down than a reading from a floating thermometer.

I still don't think this is a temperature problem. With the water at 43 degrees, the fish should be fine.

 

[WaterGardener]

mrsclem, did you also do water changes or anything else with the pond? I know some people swear by Melafix. I've never been a fan, and this is the only study I've seen about it.

Here it is: https://www.researchgate.net/public...icacy_for_MELAFIXR_melaleuca_cajuputi_extract

It probably won't change your mind, but this is a legit study and not just my opinion.

 

[mrsclem]

We had a holding tank that was part of the pond that had gone stagnant and was full of rotted leaves. That caused our problem. When we found the first few dead koi we started to drain the pond and found a lot more so yes, we did a water change. Study was done on goldfish and clownfish. Doesn't say what problems were treated. I had severe fin rot on all but 2 koi, several that had tails that were completely gone. 3 weeks of treatment, 90% of koi survived and even regrew fins and tails. I keep both meds stocked now.

 

[WaterGardener]

I'm glad you were able to save the fish, but I would suspect that it was because you corrected the water problems and gave them an environment to live in that they could heal themselves. I'm sure that's not what you believe, and I'm glad it worked out for you. But personally, I doubt it was the Melafix, just good water.

My motto is always fix the water first. Most problems can be cured with good, healthy water. And no medication will work if the water is still polluted.

Just my 2 cents worth.

 

[12cats]

mrsclem, did you also do water changes or anything else with the pond? I know some people swear by Melafix. I've never been a fan, and this is the only study I've seen about it.

Here it is: https://www.researchgate.net/public...icacy_for_MELAFIXR_melaleuca_cajuputi_extract

It probably won't change your mind, but this is a legit study and not just my opinion.

I will check it out.

 

[Faebinder]

It's not cold water. Something else is not right.

 

[Lisak1]

Melafix does nothing

I read the link you posted - I don't think it's accurate to say it "does nothing". What I read was that it does not change the water parameters (which would be a good thing) and it did not appear that the results user report were due to antibacterial properties. "This topic will require further research and possibly an in vivo study." I read that as "people report that it works; we just don't know why".

 

[WaterGardener]

Maybe that wasn't a good way to put it. But it had no effects on the pathogens they tested it against and they stated that it had no antibacterial properties. Don't most people use it to treat bacterial infections? To me that sounds like it doesn't work for what most people use it for.

People often think that things work that really don't, when it is something else they have done that really cures the problem. Think in terms of placebos.

 

[12cats]

Do you have any idea how much baking soda to add for 8000 gallons of water?