Koi pond 💀

In case anyone was wondering house wash will kill koi fish. I was extremely careful around the pond but I guess I let a little mix get in the pond and killed some fish.

I know this is not news to a lot of people. And honestly isn’t even news to me but i guess I got a little complacent last week and now I’m sharing my failure with you all with the hopes you guys won’t let it happen.

Good luck out there and don’t dwell on the past. (That was for me).


sorry to hear that, I certainly hope they weren’t very large and hopefully not rare. that could get extremely pricey, plus they will want a whole pond cleanout, and filter replacement.

What would you have done different?

I don’t do any jobs with Koi ponds near by. Those fish can get ridiculously expensive and I heard the same thing. It doesn’t take much to kill them.

I washed the backside of a home on a rainy day with a koi pond about 20 ft back that had plastic lining under it. I think the lining and rain is what saved me because a good bit of bleach probably soaked into the dirt but not through the plastic and was diluted due to all the rain. Ponds make me nervous too

I wouldn’t doubt it…

Back in my Carpet Cleaning Days, We had to be careful of those fancy in home aquariums… Some chems where toxic to the fish and the filtering system would pump it in to the tank killing all the fish… Never understood how, Maybe the air bubble system? Not sure…

I wouldn’t have done the job. Knowing how careful I was and they still all died. Not worth the liability. I guess if the homeowner was dead set on me washing it I would just refused to wash the side of the house it was on. Basically eliminate any chance anything could get in it.

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That is correct, a light overspray with house mix will kill them (many fish for that matter), These properties should be avoided. It’s almost certain to give a business a bad name, just not worth it.

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It happened to me a couple years ago. I’m an animal lover and I felt horrible. Thankfully, the homeowner was understanding and after all it was an accident. I had a heavy tarp over the pond and the runoff collected on it and the weight was just too much. I was on the second story deck when it happened and I rushed down and immediately pulled the tarp off. By that time the damage was done. I bought them four new fish to replace the two that were in there. I still feel horrible about it today. That customer even referred me more business after the fact which surprised the heck out of me.


We did one like that last year. We put a tarp over it and secured it well. We didn’t want to do it initially but they really wanted us to, so I told them we would use all these precautions but no guarantee no fish would die. Had them sign a waiver understanding what we went over with them. I figure I signed so many waivers when I’ve had surgery, (risked involved that the medical team not responsible for) whats the difference in this case. They totally understood the risk and wanted it done, all turned out fine. I lay it out to them and give them options of what we can do and do the job accordingly. But yeah, no fun if something happens regardless of a waiver.

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One trick I learned about Koi ponds was this. Before putting the koi in the pond (after everything is ready), get a bag of goldfish. Let them test the water out., they are pretty cheap for a bag. they will help put elctrolytes in the water. I’m not one for animal cruelty, but I am also not one to kill off expensive koi either.

I kept saltwater fish for many years, as a result I worked part-time for a specialty exotic reptile and fish dealer. I learned a great deal about the nitrogen cycle (look it up if you keep fish). One thing for certain, they are extremely vulnerable to even the smallest amounts of toxins. I turned down a job TODAY due to a Koi pond’s proximity to the home. I am here AFTER I turned it down to see what (if any) steps were taken by any of you to protect them. I’m not the type to get a job and then learn how to do it… Appreciate so many of you here. So my 2 cents, PASS ON THE PONDS.

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Personally, there’s little to nothing to be gained in doing it… no one will give you props for washing the house without killing their fish (no matter how likely you tell them it might be). But they will sure look at you badly if it happens. It’s not all that hard to avoid damage, but even if you sell folks on “we do the most to prevent it from happening”, that won’t improve the perception if…

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ask to have fish removed and pond treated afterwards. if they can they will.

Thats not a bad solution; however, it stresses the animal being moved and yep you guessed it -stress alone can kill fish.

This is my solution:
Mr. xxxx,
I kept saltwater fish for many years and understand how vulnerable ANY fish is to even the smallest amounts of toxins. Being an animal lover and having a deep respect for them and their environment we are going to have to decline offering our services to you.

I appreciate your consideration for your animals and your concerns are very important ones. I want to thank you for reaching out to Powermount Power Washing Inc for your needs.

I wish you the best and hope you enjoy your summer outside! Koi are beautiful fish!

Thank you again for your consideration


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My very first “job” I did for a close family friend, resulted in 2 dead fish. Her kids still refer to me as a murderer. She laughs about it, cause she hated them (the fish).

2 years later I decided to take a job where the side of the house was not very bad, just the gutters needed hit. The pond was maybe 10 feet from the side, it was small enough that I could easily cover with a tarp.

I successfully pulled it off. However, the added stress of having some SH pool up on the tarp and panicking as I tried to remove the tarp was not worth the money I charged.

Haven’t encountered one since, and will politely turn them down going forward.

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Get some pond dechlorinator. Not recommending this brand or source specifically, but the idea: https://www.homedepot.com/p/TOTALPOND-16-oz-Chlorine-Remover-53933/202017070

Still need to be extra careful. The chlorine will burn up their gills and they will be long dead before the gills can grow back. Plus the dechlorinator can harm the fish, so ya cannot just go overboard with it.

It’s not a save-all, but it can help provide an additional buffer.

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I’m very familiar with dechlorinator, also calcium levels, specific gravity, salinity, Ph, copper, alkalinity, hardness, ammonia, nitrates, nitrites, and temperature etc., Take whatever precautions you want. I’m not risking the reputation of my 1 year old company for a $300 house job. Like Jatkinson said above:

Gotta go it’s warming up finally…

I have cleaned around fish a few times. Never had an issue, but always very nervous. You can always work around the things you can see, but what always scares me is what I can’t see. Like is the water coming down a gutter spout that leads back to the pond or is there, some how, runoff that is seeping in where I am not able to see it. One time, I did a job for a veterinarian and she said don’t worry about it, “They’re just gold fish.” I never heard anything about it. One time we cleaned and stained a deck over two really large KOI ponds. I know we got chemicals in there and even stain. There was no problem and of course it was discussed with the home owners up front. Moral of the story, if you are scared be careful, but you can always turn down the job. I have turned down some jobs when I was using employees and I was not able to be onsite.