Have lost six large koi in past three months

[Ellis Smith]

I have an 8000 gal pond with epdm liner and two 10,600 gal/hr pumps, each supplying a large capacity biofall. The pond is three years old and water quality tests good with the exception of general hardness and alkalinity. These are roughly 180ppm and 232ppm respectively. Leaves, pecans and mistletoe drop from three trees, pecan, red oak and mesquite, that surround the pond. I had 16 large koi 12-20 inches and around 100 fry in the 3-5 inch range. In the past three months six of my large koi have died and one is currently sick. There is no obvious external parasites, no discoloration and gills look good to my uneducated eye. The fish just go belly up and may float but generally sink to the bottom. They stay this way for several days before dying. I am at a loss. Attached photos are of my most recent casualty. Any suggestions would be appreciated.

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The koi in this photo appears emaciated. I had not noticed that in the earlier deaths nor did I in this one until examining the photos.

 

[DrCase]

I have always heard that mistletoe was poisonous
Could the koi be eating it as it falls in the pond.

 

[Ellis Smith]

I believe it likely that they could have eaten some of the mistletoe berries and this was one of the concerns that I had when realizing the problem was epidemic. I knew that mistletoe berries could kill dogs but had not read anything concerning their effect on koi. Assuming this is the problem is their any remedity after the fish becomes ill?
Thanks,
Ellis

 

[stroppy]

in the first photo just above his gills are those little wart like bumps ?

 

[stroppy]

i just found this site
http://www.sanangelopondsociety.com/plantstoxictokoi.htm
sorry to post it here but i wanted Ellis to see it maybe after someone can move it for me ..

 

[ctrgojo]

:banana: Oak is on the poisonus list too

sorry to hear about your losses
Your pond is very beautiful, any way you can maybe suspend a net abouve it to keep all the leaves and such out?

http://koiclubsandiego.org/library/toxic_plants.php

after looking at your pictures it looks like you maybe have elephants ear in there too?

 

[Ellis Smith]

Wow! Didn't realize that oak is a problem. Is it from the leaves or acorns? I can't imagine koi eating the leaves and my tree does not produce acorns at this time. Most leaves end up in the skimmer but many do not. My wife has mentioned netting but the size and layout is such that it would be difficult. Thanks, Ellis

 

[Ellis Smith]

Stroppy,
Looks like bumps in the photo but I didn't notice it while inspecting the fish. They do not appear in a photo that I took of the other side. I have another one that is sick now. I will check that area to be sure.

Ctrgojo, Plant that looks like elephant ears is tara. May be the same for all I know. This is its second year in the pond. Thanks, Ellis

 

[koikeepr]

stroppy is right. On the one side of the fish on the head there are bumps...

 

[stroppy]

i wouldnt like to guess what they are but im sure koikeepr or others will be able to help you

 

[stroppy]

ps yes elephants ear is taro

 

[DrDave]

Ellis
Those photos show an otherwise healthy but starving fish. It almost looks like it just stopped eating. I have an Orengi that I took out of my juvinile pond that was not eating and moved him to a tank for the winter. He nearly died before I got him to eat. Now he is fine but still is a little thin compaired to 2 others I have in there with him. I never considered poisoning from plants.

I have a lot of taro in my ponds and have had it in there for several years. A friend that has a pond almost as big as yours has a lot of taro in his and has had no problems.

Keep us posted.

 

[Ellis Smith]

I checked the San Angelo Pond Society web site and discovered several potential culprits, mistletoe, calla lily, oak and tara. Have followed ctrgojo’s advice and covered one end of the pond. It was easier than I thought. Have also began to cut mistletoe from surrounding trees. Moved another sick koi to hospital tank and increased temp from 42 deg to 62 deg over 20 hours. This may have been too fast because it appears that he is sloughing the slime coat.
Texas is a big state but San Angelo is only 75 miles from Abilene. It is ironic that someone from Essex England had to tell me about their web site.

 

[stroppy]

the power of google ellis ...i only hope it helps to save your fish

 

[DrDave]

I would not worry too much about the Taro. Like I said, I have it and so do many of my customers that buy plants and koi from me. None of us are experiencing these problems. I would look to the stuff that falls into your pond and has a chance to disolve as it deteriorates on the bottom. Berries floating could also be the culprit.