My Koi disaster

I am a newbie to the forum and need some help.

I have a 165 gallon pond in the back yard and have had difficulty keeping Koi alive in it. From what I can tell I am having an issue in the fall where all of a sudden the ph just bottoms out to just over 6. Last year I thought it came from the small farm field next door when they spread lime.

I had one large female which was in the pond for about 4 years (the only one that lasted thru the carnage) Last year they spread lime twice..the first time it was enough to show up under the hood of my brand new car while I was getting it ready for a show. I lost a few of her babies that time but did not know that was the cause. The next week I saw them hit the field again and the next day the female was laying completely on her side at the bottom of the pond. I quickly checked the water and discovered the ph issue so I put baking soda in the water to level the ph off. She recovered after a few days.
This year they have done nothing to the field and out of the blue overnight she went to the bottom and was totally on her side. I made sure she was still alive by scooping her to the surface and after that she floated. I leveled the ph off again but she died the next day.
I had one Koi left that I bought over the summer and a week later ( 2 days ago) he was found floating sideways on the surface still breathing. The ph again bottomed out. So I have leveled it off and he has gotten slightly more active but is floating sideways just under the surface almost motionless. If I set him upright you can feel that he wants to swim but its almost like he is paralyzed.

I still have babies from the last two years, a comet (5 yrs), and 2 mixed gold fish (4yrs) in the pond that appear to be fine.
The Koi that died have no obviously injuries if you look at them.

Any ideas if there is something else going on besides them liming the field next door.

Thanks

 

Do any leafs get in the pond?

 

Not really, I have a net over the whole thing to keep that stuff out and the birds. Some smaller seed pods do get in but I try to get them out before they sink and decay.

 

Well I'm out of ideas, I was thinking maybe a increase of foliage would cause a tanin spike. Your positive that they arnt spreading any pesticide? There are laws that prevent people from spreading things that can get into their neighbors yard. They should be checking wind direction and dumping in the opposite direction of your home.(are we talking a plane drop or just manual spreading) either way. Be sure they are aware of the pond and the effect they might have on it.

 

SH, where in the US do you live? Lots of places get an huge increase in rainfall in the fall. If this is true for you, everything your neighbors have spread on their fields, including fertilizers, pesticides, and especially mulches (more on this one in a minute), during the dry summer is going to be washed into your koi pond.

Assuming this is the case, mulches are basically nothing but tannic acid, which would lower your pH, but probably not by the huge amount you're talking about unless
1) it's not an organic mulch, but instead a heavily chemically enriched mulch that contains other acids aside from tannic acid (a relatively weak acid)
2) it's tanic acid from mulch and/or manure reacting with another chemical they're spreading, leaving extra H+ ions as a biproduct

This is a weird question, but what are they growing/raising? if they have to worry about certain pests, especially the potato bug, the specific pesticides used to combat these critters are pretty hard core chemicals that will react readily and poison your water quicker than you can say "potato famine".

Unfortunately, I'm willing to bet the drop in pH wasn't from the lime, simply because lime is applied to soil specifically to increase the pH. It's a base. It's likely from something else; possibly something applied with the lime, but it could be unrelated entirely.

Does it snow this time of year where you are? If it does, what does your county use to "salt" the roads? Many counties are now using salt with other stuff which can be pretty toxic for fish, and which can lower pH.

My best bet on what I know so far: mulch + fertilizer/livestock poop + rotting vegetable matter from crop by-product = bad news bears.

 

Also, take your koi out of the pond if you can, put him into a hospital tank with LOTS of active carbon in the filter. Start the tank off with water from the pond so the chemical change doesn't shock him, but do a 10% watch change every 12 hours for week or so. This plus the active carbon should get whatever's in the water out. Give him something to help with his slime coat, and dose him with a mild antibiotic like melafix to prevent any secondary infections resulting from stress. Keep an eye on him, feed him lightly, only what he'll eat. Give him an airstone if you can, just to help keep his O2 up. If his gills received any kind of internal chemical burn from some water contaminant, the scar tissue will make it hard for him to absorb O2 as well as he normally would; the extra O2 will help him to heal.
Also, keep an eye on the other fish for any others exhibiting similar symptoms. Do they eat anything that lives/grows in the pond with them? If this is so, try to figure out a way to stop that from happening (foodchain magnification of poisons; I can explain it if you want but the "why" doesn't seem terribly important just now).

 

If you can give me a state and county, and tell me what your neighbors are growing, I can do some digging and let you know what the top 10 contaminants you have to watch out for would be.

 

Welcome to Fishlore SilverHawk.

An unstable pH is a direct result of not having enough buffering capacity in the water. Buffers act by absorbing (neutralizing) acids that are introduced into the water column by what ever means (quite often just caused by decaying debris), thereby protecting the pH and keeping it stable. The more buffering capacity water has the more of these acids it is able to absorb before the pH is affected. You've already been trying to buffer your water by using baking soda, but the problem with using baking soda is it has to be added any time fresh water is added to try and maintain a stable pH.

Do you have test kits that will test for GH/KH (General Hardness and Carbonate Hardness)? KH measures alkalinity also referred to as buffering capacity. If you can test these two components along with the pH information, we will better be able to help you resolve this issue.

Other valuable information at this time are test results for ammonia, nitrites and nitrates. Ammonia can be in a fairly non toxic form known as ammonium when pH levels are under 7.0 but an increase in pH above 7.0 makes ammonium convert back to ammonia and suddenly fish can be exposed to lethal doses of this toxin, so knowing all of this info will help us help you divert a potenial disaster for your fish.

 

I'm in Delaware farm country go figure. The farmer put soybeans in the field but he just left them and did not harvest anything. I didn't see them hit it with anything this year including the lime. Last year the first time they hit it with lime it blew all over into my yard.... just because it got underneath the closed hood of my car. I put in a sludge block and slime coat plus at the beginning of the month. The pond is crystal clear not really anything laying on the bottom. I also have a fern in there and another plant but they really aren't dying. The weather has been decent not really a lot of rain.
Funny that's its only the Koi?
I just went out to look at the last Koi and he's done... the kids just buried him.

Could they just be too big for the pond? They outgrow everthing else and quickly...
"Big Mama" was over a foot long and weighed a few lbs. Everyone said she was too big for that pond but she was that big for over 2 yrs? The one that just died was about 7 inches long and about as big as the comet and both "mutts"

 

the soybean planting is to usually help revitalize the soil from all the nutrients removed from other plants.

the lime also most certainly raises pH. It can actually raise the pH almost off the charts of the high range test kits.

I would suspect that it is a pesticide of some kind that would do what you are describing.

 

Common pesticides use on soybeans include:
Prowl
Treflan-probably most common.
Tolban
Surflan
Cobex
Basalin
And I know the needed ferts are molybdenum, potassium.

 

yeah that's a lot of evil for fish right there.

 

Another thing to remember is that Koi or more sensitive to water quality issues than regular goldfish. That could be why the Koi are reacting but the regular goldfish are not. Does the pond have a liner? It could be something leaching up out of the soil. My sister's pond had issues every fall - her fish would get very droopy and she would occasionally lose one. Only in the fall. She replaced the flexible liner (that had leaks and holes and such) with a large plastic stock tank. No more problems. It could be something leaching in from the soil, or from the roots of plants or trees in the area that have penetrated into the pond.

 

x2 to what gremlin said. and P3's right; (thanks for digging those up SK!) those are pretty nasty. Treflan and Cobex especially I've seen some pretty nasty effects from on non-target species (I don't have personal experience with the others, but if you look them up, some of those chemicals shouldn't even be legal, imo); especially lasting and compounding health issues (what's enough to kill a tiny bug isn't necessarily enough to kill a large fish, but can still be enough to make them sick). I've also seen it mess up a whole batch of fry pretty hard core (carp was exposed to high doses of Cobex while pregnant).

The other thought is that while koi are more sensitive chemically, they're also really tough fish in that if there's a food that's particularly tasty, it'll beat up a comet to take the food (I have seen this happen; it's not constant aggression, just the biggest baddest fish taking what he/she wants to eat first; totally normal behavior). If this tasty food happens to be a bug which eats in your neighbors fields, and then breeds in water and dies off in the fall, you could be in for trouble. There are insects which are resistant to various pesticides (not as abnormal as you'd think), or you could just be getting insects which only eat got a little of the poison (the farmer isn't likely to spend too much on pesticides for a field that's essentially lying fallow for a season). These insects die off, or get slow and weak in the fall, and your fish eat them. Koi and goldies love bugs (my common eats wasps, idk y but he likes them); but when each bug comes with a tiny dose of poison, eventually that adds up and can cause some serious damage to the fish that are eating them (this is called biomagnification; , I'm not making this up). If the poison is being ingested in this way, a little at a time... I'm not going to say there's nothing to be done, but I'll admit that I have no idea how I'd fix that. If you like, I can email one of the ... idk what they're called, but they're veterinarians with a specialization in ichthyology, at the animal hospital in my town (working a block from Cornell University has some perks), or somebody in the agricultural department, and ask them if they know any good treatment methods for fish who've been exposed to pesticides.

Just took a second look at Gremlin's post (very excellent point, btw, G) and it gave me an idea. SH, what's growing in your backyard w/in, say a 100m radius of the fish pond? I don't need to know how many or how big, but just give a rundown of the plant species you recognize. Several trees (most notably the black walnut) actually leach herbicides out of their roots to poison competition (pretty hard core trees); and there are other plants that have a similar defense mechanism.

 

The pond is one of those plastic shells. I have grasses growing around the pond that's about it. I can't have trees because of my septic field (no where close to the pond.

Its a shame 2 of the last three Koi I lost hurt my feelings a little bit. They were probably 2 of the coolest looking I've ever seen... too bad I could never get a photo.
"Big Mama" had a bright neon orange body with white/silver underneath and a black almost skeleton pattern on the top with large ice blue eyes.
And I had a male butterfly that was reddish orange with silver looking sides. I think drastic temperature change got him and 4 others (3 babies) last winter. It went from 45 to like 10 overnight and froze everything 1 inch thick but the puck heater.

Guess the safest bet is to just stay away from the Koi from now on. If they are that sensitive its not fair that I keep throwing them to the "wolves".

At least I have lots of her babies both out in the pond and in three separate aquariums inside.

Thanks to everyone for all the advice. I just wanted to see if anyone had something like it happen to them and if they had a definite solution.

 

Welcome to Fishlore SilverHawk.

An unstable pH is a direct result of not having enough buffering capacity in the water. Buffers act by absorbing (neutralizing) acids that are introduced into the water column by what ever means (quite often just caused by decaying debris), thereby protecting the pH and keeping it stable. The more buffering capacity water has the more of these acids it is able to absorb before the pH is affected. You've already been trying to buffer your water by using baking soda, but the problem with using baking soda is it has to be added any time fresh water is added to try and maintain a stable pH.

Do you have test kits that will test for GH/KH (General Hardness and Carbonate Hardness)? KH measures alkalinity also referred to as buffering capacity. If you can test these two components along with the pH information, we will better be able to help you resolve this issue.

Other valuable information at this time are test results for ammonia, nitrites and nitrates. Ammonia can be in a fairly non toxic form known as ammonium when pH levels are under 7.0 but an increase in pH above 7.0 makes ammonium convert back to ammonia and suddenly fish can be exposed to lethal doses of this toxin, so knowing all of this info will help us help you divert a potenial disaster for your fish.

you may have something there.... I always test the PH and make sure I add slime coat plus and sludge blocks religiously along with vacuuming out the bottom junk. to make sure the ammonia levels don't get too high ....don't think I have ever checked the KH
Could the change to low temps in a short period of time be bottoming out my PH?

 

No the temperatures wouldn't affect the pH other than the rate of which organic matter tends to decompose. Tannins from bark, roots, and other natural occurring substances possibly introduced with the run in of rain water, fish respirations, and maybe most importantly, nitric acid which is a by product of the nitrogen cycle are all things that affect pH. If you are combating ammonia levels, this puts the beneficial bacteria into overdrive trying to keep up with the production of ammonia and nitrites which means if this is the case, then the pond is still trying to establish a cycle. During the cycling process, pH fluctuates a lot. Nitric acid will slowly work away at pH if water exchange isn't sufficient especially when limited plant growth is involved but in the cycling process, the changes happen relatively fast and reach higher and lower than expected pH levels as compared to the same water that isn't being affected by the nitrogen cycle. Again though, anything that can affect pH will have less or even no effect with good KH levels. (In my experience the nitrogen cycle always has some effect)

So, if we can determine the GH/KH levels, and if they do happen to be inadequate, we can at least minimize the chance of pH instability and even pH crash.

Why would you be really only noticing this event in the fall? Well, I think your GH/KH levels are always in the range of too low. That doesn't mean your pH is always low, or what you would consider low going by your past experience with it. What it does mean is it doesn't take much to affect it. In the spring and summer, maybe (I am guessing a little here) you get a decent amount of rainfall and things get diluted more, so maybe in the fall you've been getting dryer weather and things aren't being diluted the same. If this was the case then it's plausible to think the build up of the components mentioned create increasingly lower pH levels, and possibly even the odd crash.