My large Koi were dead this morning

[Rayma]

Recently I covered my pond with a large net to help contain the above maple leave and Elm tree seeds from the fall defoliation. I have three beautiful maple trees that cover my ponds area. So I covered it with a net to catch the leaves. It has been about a week and a half the the screen was placed over my pond. Part of it laid on the water and other areas were not. This morning when I went to feed my fish the three 12” and three 5” were dead. All my smaller fish are fine, as of now.

I immediately removed the net. Did I suffocate my fish? My pond has two large water falls that aerate the water. These Run 24/7.

 

[addy1]

Did you test your water? Ammonia etc may have gotten out of control.

 

[bagsmom]

Sorry to hear this!

 

[j.w]

Wonder if any kind of chemical was on the net? So sorry for the loss of your fish. What kind of net was it? If it had holes in it I don't know how it could kill your fish. They would get plenty of oxygen w/a net that has large holes in it.

 

[Rayma]

Did you test your water? Ammonia etc may have gotten out of control.

What causes ammonia to get out of control?

 

[Rayma]

Wonder if any kind of chemical was on the net? So sorry for the loss of your fish. What kind of net was it? If it had holes in it I don't know how it could kill your fish. They would get plenty of oxygen w/a net that has large holes in it.

No chemicals. I used it before. Very strange only large Koi

 

[Lisak1]

I'm so sorry! Generally when the bigger fish die first you suspect oxygen deficiency. Could the leaves have trapped gasses in the pond?

 

[mrsclem]

If the net was in the water and covered with leaves then it is possible the oxygen level got to low.

 

[Mmathis]

I’m so sorry! That’s always a devastating discovery. It’s important not to allow the netting material to come in contact with the water. If you can, make a frame to support the netting. PVC works well as a frame. I would make the frame where there is a slant so the leaves will slide down and not collect on the netting. Or another solution would be to place a couple of blow-up beach balls under the netting. The leaves will collect and will still have to be removed, but it keeps the net off the water.

You didn’t mention the size of your pond. How big is it?

 

[Rayma]

I’m so sorry! That’s always a devastating discovery. It’s important not to allow the netting material to come in contact with the water. If you can, make a frame to support the netting. PVC works well as a frame. I would make the frame where there is a slant so the leaves will slide down and not collect on the netting. Or another solution would be to place a couple of blow-up beach balls under the netting. The leaves will collect and will still have to be removed, but it keeps the net off the water.

You didn’t mention the size of your pond. How big is it?

My pond is about 1400 gallons. The net had only been on for a week. We were waiting for our new net with the PVC. I just wanted to keep the leaves out. Our wing has been bad. The net was lying atop the water but not all over. There were several areas that were clear of the net. I checked my ammonia level and it is 0. I am baffled.

 

[Rayma]

If the net was in the water and covered with leaves then it is possible the oxygen level got to low.

I keep the leaves blown off the net. It was only on the pond for just over a week.

 

[Rayma]

I'm so sorry! Generally when the bigger fish die first you suspect oxygen deficiency. Could the leaves have trapped gasses in the pond?

I keep the leaves blown off. What kind of gasses would get trapped in a pond? My pond has a 3’ waterfall and a brook type fall. Plenty of aeration.

 

[Rayma]

Did you test your water? Ammonia etc may have gotten out of control.

I tested the water and ammonia was zero.

 

[Rayma]

I tested the water and ammonia was zero.

Ammonia level is zero.

 

[Rayma]

What causes ammonia to get out of control?

Ammonia levels is zero.