Summer die-off - Need advice

[DTown]

Spraying within 30 feet followed by a rainy or windy day may cause some overflow. In a pond these herbicides seem to kill silently.

I had a significant fish kill from some spraying near the pond x2 and both times it didn’t dawn on me till weeks later that the fish kill was related to it.

Did you spray intermittently such that fish died slowly.

I can't convince my brain to pull up that detail...

 

[Meyer Jordan]

Nitrates - 0
Nitrites - 0
Ammonia - 0
pH - 7.4

Do you know what the GH and KH levels are?
What amount of sediment do you have on the bottom of the pond?

 

[MitchM]

Since all the fish are gone, I would drain clean and refill it before winter sets in.
Leave a small submerged pump running.

It's too bad we did't hear about this beore all the fish were gone, water temperatures and some readings taken at the time may have helped.

 

[sissy]

Plus you can test your water for chemicals like those with a test kit you can buy just about any hardware store sells them here .I guess because farm ponds are so important .I know the EPA gave me one free .It took Marty 2 weeks of fishing the dead ones out .They did not all die at 1 time .It was a long slow painful time for Marty and his girlfriend .Glad that he was not using any of the water from the pond to water anything and the cows and horses were in another field .I know the said that the poison would get weaker over time ,but not to use it .Rain and snow I guess they figure will weaken it .Not sure what you would do to drain a farm pond .But the fish he kept were for eating .

 

[bettasngoldfish]

I lost all the fish in my pond a few years ago. I'm 99.9% sure it was from my neighbors spraying the bushes along the fence line with insecticide (the fence separates our yards and my pond is fairly close to the fence)

I have seen the same neighbor pouring bleach in her driveway. For what reason I can't imagine.

My husband caught them just in time this year when they were getting ready to spray the fence line again. He explained that we had fish and to please not spray near the pond as it would be dangerous to the fish.

 

[barryian]

Greetings everyone. I've been a member here for a while and do a lot of reading, but can't remember if I've ever even posted to the forum. I have an 850 gallon pond, about 2 feet deep at the deepest point. I have a waterfall and a 50 gallon filter, using water hyacinth as media during the summer. I feed the filter and waterfall with a 2400gph pump. I built the pond about 15 years ago, and added 4 fish the first and second years. From there, the population increased to about 40 fish a couple years later and stabilized at that level for a couple years. Soon after, the herons found my pond and removed about half of my fish. I added a net, and though the herons can't get to the fish any more, the fish population remained in the 20-25 range until this summer. That was fine with me. It was a minimal effort to keep the pond and watching the fish while sitting on the patio was great.

This summer, I started seeing floaters. First it was 1, Then a couple days later there were a couple more. Then another the next day. This kind of pattern continued for several weeks. I was distraught. I tested the water. No ammonia, no nitrates and no nitrites. pH 7.4. I even doubted that my water test kits were accurate, so I brought a sample to my fish store and had them test it. Same results. The water seemed to be fine. After the first few fish died, I took a closer look at the victims. I could see no ich, no parasites... checked their skin, mouths and gills. Nothing visible. I treated the pond with melafix, but that didn't seem to help. And so now, as my water lilies die back, I see that none of my fish remain.

(are you guys still with me? Thanks for reading this far!) So, my question is, what do I do this winter? Do I drain the pond and leave it empty over the winter? Do I drain it and then refill with fresh water now? In the spring? Do I do nothing and just put some more fish in in the spring? Your advice is appreciated.

Kind regards,

Dave Town

I haven't read through the forum above but that's not a large pond. I have 10 koi ( large from growth ) in a 2000 gallon, 4 foot depth pond. I'd never add more as it would overcrowd my pond and deplete my oxygen. My filter is oversized and can certainly handle the load.

If rain didn't wash off chemicals, weed killer etc and you have a high enough pH buffer (kH ) to know you aren't having day/night pH crashes, then oxygen could be a problem do to overcrowding. I'm assuming you've thoroughly
tested all parameters?

 

[DTown]

Thank you all for your input. I do not have the kH numbers. I'll have to get a hardness test kit for next time. There is no runoff that gets into the pond. It is a lined pond, and the top edge is a couple of inches above the ground level. Water never lays in the yard, so having runoff enter the pond is something that doesn't happen. If we assume that it was some sort of insecticide or herbicide, would have running a carbon filter helped to remove those chemicals? I remember I used to do this when I had my 135g salt water tank, when I had a flatworm infestation. I put in the chemicals to reduce the worm issue, and then had to run carbon to remove the chemicals. Maybe I'll set up something to run carbon on a regular basis if this would have helped.

The fish load was about half of what seemed to be the natural limit of the pond. After a few years of running, the population had stabilized at about 40-45 fish. That was until the heron got to them. The fish population never recovered to the previous levels. One other thing that made me think that it was not an overload situation is that as I lost fish this summer, the bio load decreased with each death and removal. So by the time that 3/4 of the fish had died, the bio load from the fish would have been reduced by 75%, yet the remaining fish continued to die. Just my theory...

There is a layer of lily roots at the bottom of the pond, however I cannot estimate how deep that layer is. I will find out when I drain it to refill. Anything to look for once I get it drained? Is there a limit on how thick I should let the layer of roots grow?

I will act on the suggestion to drain the pond and refill before the winter arrives. Thanks for that advice MitchM. That was the path I was leaning toward, and really just wanted your opinions on the best path to take in this regard.

Thanks again for all your help. I appreciate it.

D.T.

 

[barryian]

Do you know what the GH and KH levels are?
What amount of sediment do you have on the bottom of the pond?

Totally agree. People underestimate KH & GH and bam, crash! Never knew what hit them. I buy baking soda by the 13LB bag @ Bj's !!!

 

[barryian]

Before draining I'd get a kit. Test some of the important readings. A pH crash can wipe out a pound overnight. The KH is a critical test. GH helps to keep the pH from rising to high .... Oxygen from over crowding, pH, Kh could be one of the culprits as they wipe out joi populations rather quickly. With all due respect to Mitch, not sure I'd do a complete drain!

 

[DTown]

Before draining I'd get a kit. Test some of the important readings. A pH crash can wipe out a pound overnight. The KH is a critical test. GH helps to keep the pH from rising to high .... Oxygen from over crowding, pH, Kh could be one of the culprits as they wipe out joi populations rather quickly. With all due respect to Mitch, not sure I'd do a complete drain!

Thanks barryian. Can I ask the thinking behind NOT doing a complete drain? My thinking is that if there are bad chemicals in the pond, I'd want to remove all of them. Start with fresh, clean water water, adjust pH and hardness and let it sit over the winter. Then in the spring add a handful of fish and let the pond cycle. Fish will multiply in subsequent years. Let me know what you think.

Thanks!

D.T.

 

[barryian]

Thanks barryian. Can I ask the thinking behind NOT doing a complete drain? My thinking is that if there are bad chemicals in the pond, I'd want to remove all of them. Start with fresh, clean water water, adjust pH and hardness and let it sit over the winter. Then in the spring add a handful of fish and let the pond cycle. Fish will multiply in subsequent years. Let me know what you think.

Thanks!

D.T.

I just went back to re-read and didn't realize you have no fish left. My initial reason was you'll eradicate the complete biofilm through the winter causing more problems such as an ammonia rise and complete instability. In 25 years, the only complete drain I did was a liner change and enlarging my pond in 2012. That wasn't a pleasant task after putting the koi back and keeping the ammonia at bay for 4-6 weeks.

With no fish, I guess it can't hurt. You can even throw a small bit of ammonia in the pond to speed up the cycle although in NJ, the cold coming up won't allow any nitrobacter or nitrosomonas to build much without filtration. I shut down and drain my bio, blowout the lines but keep my Savio going via the falls with a 1000 watt de-icer directly in front of the savio. Water travels through, heats enough to keep water at 43F - 45F minimum. I built a minimum / max temp regulator I saw on Youtube so the 1000 watt is not running unless temps fall down to 34F. Saves some electric. I start it all back up on last day of Feb or early March. Ammonia is never an issue.

Sorry, got off on a rant but ideas are always good. So, it would be nice to know what killed the fish. Even draining would still make it nice to know so it doesn't replicate some day. Oxygen without a meter is hard to diagnose unless you saw your koi/fish gasping at the surface a lot during the warmer months.

I always go back in my mind's eye to KH and oxygen more than a contaminant. You've checked your pH, but did you check it each morning and each night to make a comparison? Floaters, a wiped out pond and pH crashes go hand in hand. Just some food for thought.

Lastly, if you do a complete water change, put a few 3-5 goldfish in over the winter. Might help slightly to start a cycle. Sorry I'm all over the map.

Any thoughts?

 

[DTown]

I just went back to re-read and didn't realize you have no fish left. My initial reason was you'll eradicate the complete biofilm through the winter causing more problems such as an ammonia rise and complete instability. In 25 years, the only complete drain I did was a liner change and enlarging my pond in 2012. That wasn't a pleasant task after putting the koi back and keeping the ammonia at bay for 4-6 weeks.

With no fish, I guess it can't hurt. You can even throw a small bit of ammonia in the pond to speed up the cycle although in NJ, the cold coming up won't allow any nitrobacter or nitrosomonas to build much without filtration. I shut down and drain my bio, blowout the lines but keep my Savio going via the falls with a 1000 watt de-icer directly in front of the savio. Water travels through, heats enough to keep water at 43F - 45F minimum. I built a minimum / max temp regulator I saw on Youtube so the 1000 watt is not running unless temps fall down to 34F. Saves some electric. I start it all back up on last day of Feb or early March. Ammonia is never an issue.

Sorry, got off on a rant but ideas are always good. So, it would be nice to know what killed the fish. Even draining would still make it nice to know so it doesn't replicate some day. Oxygen without a meter is hard to diagnose unless you saw your koi/fish gasping at the surface a lot during the warmer months.

I always go back in my mind's eye to KH and oxygen more than a contaminant. You've checked your pH, but did you check it each morning and each night to make a comparison? Floaters, a wiped out pond and pH crashes go hand in hand. Just some food for thought.

Lastly, if you do a complete water change, put a few 3-5 goldfish in over the winter. Might help slightly to start a cycle. Sorry I'm all over the map.

Any thoughts?

Thanks barryian,

Yes, adding a few fish for the winter makes sense. I'd feel bad doing it though, just because of miserable conditions in the pond over the winter (with the ice, going deep and getting slow, no food, you know the deal). I may just wait for the spring to add the fish. I was figuring on adding just 4 or 5 anyway, and then let the pond develop as it will.

Yes, your'e right. Thanks for the ramble. More ideas are better. Sometimes you can draw on those thoughts to make improvements to your setup. Never any harm in reading new opinions and facts.

Thanks again!

D.T.

 

[MitchM]

Actually, adding a few fish when it's cold does not make sense.
Nitrifying bacteria populations develop very slowly in colder temperatures so the fish will wind up living in higher ammonia concentration levels which will damage their gills.
Best to wait to add ammonia or a few small fish as the water is warming up in the spring.

 

[DTown]

Actually, adding a few fish when it's cold does not make sense.
Nitrifying bacteria populations develop very slowly in colder temperatures so the fish will wind up living in higher ammonia concentration levels which will damage their gills.
Best to wait to add ammonia or a few small fish as the water is warming up in the spring.

Thanks for the input, MitchM... With that info, I'll definitely wait until spring to add my new friends...

D.T.