A friendly reminder for Koi hobbyists.

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I've been keeping kois for about 6 years now with my dad. He does most of the work, but I've saved the day several times. We've had our casualties now and but not in the last 2 years.

A few months ago, I saw my Mom hanging several orchid pots over the settlement tank filter. I asked her to remove them fearing contaminated water may harm the fish. She did move them.

This morning, my Dad told me there are four dead fish. We looked at them and tried to think of all the different scenarios: air, water quality, sickness, food from China, old age... But nothing made sense. I would have blamed the food if it were from China and settled at at, but it was made in Minessota.

I walked away feeling a bit sad, but still thinking of the cause. Sometime later, I was reminded of the hanging orchids and came out to check. Sure enough, there were about a dozen orchids hanging over the settlement tank filter. Some of the orchids were just purchased. I would think nurseries use a consistent regiment of fertilizer to keep their plants so healthy. And derived that the water drained into the pond and killed the fish. I am 55% on this.

I hope my lesson may help you deal with your pond. Try not to let other people get in the way of problem prevention and good judgement. This is an expensive hobby, but it's not the money to us when our kois pass. They were my pets and I feel attached to them.

...but you may use money to reason with potential problems.


24" kohaku
24" kohaku
26" matsuba with white head
28" ginrin ochiba

[An Ly]

Sorry for your lost, as a koi hobbyist most of us have gone through once or twice, and learn from our mistake, mine was overcrowding.

An

[aquitori]

Sorry to hear about the fish. How big is the pond?

[Flounder]

You're not the only one who had problems. A friend told me that his brother was fertilizing the yard and somehow stumbled and dropped some fertilizer in the pond. Well you can guess what happened to all the koi.

[bekko]

Keep looking. It probably wasn't the orchids.

-ste veh

[MikeM]

I agree with S teve. It probably was not the orchids... but maybe. The fertilizers used on orchids might have resulted in an ammonia spike if they had been recently fertilized, but so little fertilizer would be involved that it is difficult to believe it would result in a sudden fish kill of such proportions. Sometimes orchids will be treated with copper-based fungicides, which would be very harmful. But, again, not likely enough residue to wash into the pond to cause sudden deaths... and every fish would be affected. If there were other negative factors at work, then I guess leaching from the orchids might have caused some fish to 'cross the line', but I think you would have noticed some issues previously. Something more was going on.

Nonetheless, you raise an excellent point. Care should be exercised with plantings near a pond. I keep numerous potted and hanging plants around my pond, but none over it. The edge slopes away from the pond so water draining from pots flows into the garden, not the pond. When I spray fertilizers on the hanging plants, I either take the plant elsewhere for the spraying, or I take care that the spray is gentle & focused on the plant so no spray drifts into the pond. (A mist of fertilizer would not kill the fish, but who needs more nitrogen added to a pond?... a keeper of waterlillies, but I don't keep plants in the koi pond.) I never use any insecticide or fungicide any where close to the pond, and certainly never anything containing copper, iron or other metals.

[KoiCop]

I, too, raise orchids and I'm with Steve and Mike -- you need to keep looking for the cause of death.

Orchids require very, very low levels of fertilizer. Our mantra is "fertilize weakly weekly." And while commercial orchid fertilizers can contain copper (the label on the one I used yesterday says .05% chelated copper) the drip through amounts of copper would be absolutely miniscule.

Inexpensive test strips are available to test your pond water for copper. Always test (don't guess) when your koi are at risk.

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I think the kois were in good condition. We have a sufficient size pond: around 15'x22', 4-5.5' deep with a 3-part filter system. The kois are very active. Two of them are friendly. So, they eat more and are quite large (ginrin ochiba in picture). The other two are shy, and eat less. Even in the summer, we don't feed so much that food would flow into the skimmer.

I'll keep looking to see if there are other possibilities.

[aquitori]

You got all of us curious of this mysterious die off. Maybe if you can get us pics of the filtration, the whole pond and surrounds by the pond.

[lildude]

Did you spray fertilizer, administer poison around your pond?