Hello from Southern MN - and please offer suggestions

[Linda in MN]

We bought this house in the fall of 2009 with a 400 or so gallon pond in the back yard. I have had aquariums for decades and know quite a bit about water quality, cycling aquariums/the pond, etc. Our winter weather is so severe that we have to either use a 1500 watt heater to keep a vent hole in the pond or overwinter the fish in a stock tank in the unheated garage. We chose the latter. The pond isn't big enough for Koi so we bought goldfish in 2010 and they have thrived, and multiplied, in the pond until this spring. The biggest goldfish is 4-5" long now and there were 16 adults (3-5")and 4 babies (1") when I acclimated them to the pond on 4/22. I know that if they all grow to full size the pond will be overpopulated but they have done well so far, even through the winters in a 100 gallon stock tank with a bubbler & 200 watt heater.

In the spring it is customary in this area to power wash the pond then refill it. We did that 4/20 then filled the pond two or three times and pumped the grungy water out each time then refilled it for the season. I got impatient and moved the fish to the pond on 4/22 and we've lost all 4 babies and 6 adults since and 3 more adults didn't look like they were going to make it as of two days ago. None of the fish will eat their spring/fall cool temperature food. Ammonia is 0.25, Nitrite is 0, pH is 8.2 and the water temperature was still only 58 degrees. Didn't bother to check Nitrate since the pond hasn't had time to cycle, especially as cold as the water is. We're running an IonGen to prevent string algae and the Copper level is 0.1-0.2 (normal to keep the string algae away and a level the fish have tolerated in previous years). I use a dechlorinator that removes chloramines and Microbe lift per label instructions.

So here is what I'm pretty sure the problem is: In a rash (and stupid) move, without reading the label instructions, I sprinkled Preen on the rocks around the pond before we power washed the pond. Then my husband tromped in and out of the pond while we were power washing it so he most likely tracked Preen into the pond. I thought a pre-emergent would be a herbacide (not a pesticide) but, after the fish deaths, I read the label warnings and Preen is extremely toxic to fish. When I realized that was most likely the cause of the deaths two days ago I yanked the fish out of the pond and put them back in the stock tank in the garage, which we still hadn't drained or removed the bubbler from. The fish seem to be improving in the stock tank. A few minutes ago I counted 8 that were more active in the 58 degree stock tank water than they were in the 58 degree pond 42 hours ago, still need to find those other two fish...

So this is what I want to ask other pond owners: We plan to pump the water out of the pond and refill it multiple times. How many times would you fill and pump the water from the pond? We cannot get all of the water out so every time so there would be residual water. Would you replace the filter pads or just rinse them a number of times? Would you power wash the rocks again? From the research I've done on the internet, Trifluralin, the active ingredient in Preen is toxic to goldfish at 145 ppb. I have my own thoughts but just wondered what other experienced pond owners thoughts are on how to rectify this stupid error.

I'll attach a photo of the pond right after we power washed it in April 2011.

 

[sissy]

welcome can you contact preen and ask them they may know the answer .If your pond was deeper you could keep them out there in the winter and maybe just keep a small heater and aerator going.Most of us here do not keep gravel or rocks on the bottom of the pond .

 

[Lisak1]

You probably hit on the answer, but you may also want to consider that the new water didn't help the situation. When you empty the pond and wash the rocks, you lose all the "seasoning" that makes your pond a healthy environment for your fishy friends. If you do want to empty and do a complete clean out, it's best to save as much of that old water as possible to re-use when you refill the pond.

Those sparkly clean rocks are nice from the human point of view, but your fish live in the water and their needs are a bit different!

 

[Waterbug]

Preen is toxic to goldfish at 145 ppb
Copper level is 0.1-0.2 ...fish have tolerated in previous years
Fish are coming out of winter.
Microbe Lift
Dechlorinator
Water temp is 58F.

Hmmm. It would hard to say exactly what is killing the fish. Pretty safe bet it's a combo of things.

At 58F the fish immune system isn't going very well and they're already coming thru a winter which stresses them.

Copper 0.1-0.2 may not kill a healthy fish. Certainly will stress them. It's like us breathing car exhaust, it may not kill us, but it sure has an effect.

Preen level may be have been way below toxic level. Toxic level testing is done on healthy fish in good conditions.

Microbe Lift contains...well no one knows. The company sure doesn't say and they aren't required to.

Did the chemical in the dechlorinator react with the copper? With the Preen? With something in the Microbe Lift? I sure don't have a clue. I like simple.

I don't know how water soluble Preen is so I have no idea whether filling and dumping would help. I assume it lasts a long time in the garden, like several months, so I'd guess it's not very water soluble at all. If you want to be sure I'd empty the pond, rocks included, Shop vac the remaining water and then wipe down the liner with clean towels (you can buy packages of these at the hardware). Replace with new rocks/gravel if desired and startup again. This time add one fish and give it a few days.

If I might suggest...

Adding water and waiting a few days and measuring chlorine level instead of dechlorinator is way, way safer. Cheaper too. Plus it gives time for other things to even out. Once dechlorinator is added measuring ammonia is much more difficult. Plus, if the fish die at least you know it wasn't a dechlorinator mistake. Unless you really need to have fish in the pond right away.

If you can wait a week or two you can even add a little ammonia from the drug store when you first add the water. That will feed the nitrifying bacteria the food needed to grow and be ready for ammonia from fish. Not needed for most fish loads, but lots of people like to add stuff to the water and so this one can't hurt as long as you test ammonia is very low before adding fish. It kind of goes back to only adding things you can test.

Microbe Lift...buy it if you must, but don't put it in your pond. It just adds waste.

Copper Ion generators push fish to the limit. In such a small pond it's really taking a chance imo. If you really want to use copper I suggest the chemical form. That way at least you have some control. The cheap ion generators don't even test copper level, they just generate ions and hope for the best. Even the high end units have problems with probes going bad.

 

[Linda in MN]

Thanks Sissy. I did call Preen and they had me call the Product Safety Information Service and who took a report and told me changing the water was probably the right thing to do, in this case, but they wanted to make sure the old water wouldn't go into any natural bodies of water.

I've also been to the garden center to pick up a replacement skimmer box net and they said when they use chemicals they rinse the containers 3 times. I suspect we will need to rinse the pond several more times since we can't remove all of the polluted water each time, all we can do is reduce the concentration of the pollutant.

Lisak1: Thank you for responding. Power washing the pond in the spring is typical in this area but I will consider vacuuming the pond instead of power washing next spring, that would allow us to keep most of the old water. We have to do something major in the spring. We have 4-5 months of continuous sub freezing temperatures (down to negative 27) so all of the nitrifying bacteria in the ponds die over the winter anyway. And, if we don't do something major, the decomposition of all the leaves and sludge that accumulate in the pond over the winter (when we cannot run the filter) would be a huge load on the non-existant biological filter in the early spring as pond starts up. I would never have done more than a 30-40% water change an aquarium that runs continuously but, due to our climate, this pond cannot run continuously. We've had 100% fish survival after power washing the 3 previous springs so I'm 99.9% positive the problem is that we got the Preen (or fertilizer, see below) in the pond this year.

And Waterbug: Thanks for your thoughts. I wish I was in AZ where I could leave the pond running all year. I just checked our city's website and it appears we have chlorine rather than chloramine in our water so I can just let the water age for the chlorine to dissipate, rather than using the dechlorinator. I need to pick up a new chlorine test kit, the charts for my current kit got wet and aren't legible any more. I will take all of your recommendations into consideration however we don't have the time or physical ability to remove all of the rocks from the pond and replace them so we're going to have to go with the filling and draining a number of times. But you may be right that the Preen lasts so long in the garden that it may be stuck to the liner and rocks, until July or longer... I may buy a few feeder goldfish to add to the pond before I add my 4 year old fish again... And I just realized, our yard was fertilized two days before we power washed the pond so we may have tracked fertilizer into the pond too...

 

[sissy]

funny preen should say it should not go into in body of water i saw there commercials and they are putting in gardens right near a swimming pool .They sell this stuff but then you put it down and then get heavy rains where do they think that stuff goes then

 

[Fishylove]

I, and I know many others on here, would never think of draining and power washing, you'd be surprised what Survives even at those temps. As far as yard and leaf litter, you need to put a net over the pond before the leaves start falling. no yard litter, less muck. Then in the spring vacuum or scoop the rest. There really is no need to do that much work. Good luck

 

[Linda in MN]

We do put a net over the pond in the fall but remove it when we remove the fish, we should probably put it back over the pond. I do worry about leaving the fish in the pond all winter. We've had heaters die two years in a row and if that were to happen in the pond we would lose all the fish whereas in the garage we see that the stock tank is freezing up when a heater dies. We have had several fish we weren't able to catch in the fall and all except one has died over the winter, and that one survived a "mild", by Southern MN standards winter.

 

[Lisak1]

Linda - I'm in Northern IL, so we have similar weather. However our pond is much larger, so that makes it more viable to keep the fish in the pond all winter, which we do. No heater - we just ran the waterfall all winter and had no issues at all, in one of the harshest winters we can remember.

We don't net our pond - or at least we haven't in the past - but we have very few deciduous trees. Our entire subdivision is pines and other evergreens. We still get pond debris however, and this year seemed to be worse so we may consider a net this winter. But I do understand why you empty and clean your pond - and many, many people do. So I don't think it's an absolute. Also a 400 gallon pond is much easier to empty and clean than a 4000 gallon pond, so that might help make the decision too!

We don't use any chemicals in our yard or gardens - mainly because I don't like the idea of coming in contact with them myself, but also because we have dogs and the pond. And I worry about the wild animals too - we have lots of dandelions, but the bees love them.

 

[Tula]

The more I learn, the more I'm afraid to use yard/ garden and pond chemicals. So sorry you lost fish and are having to go through so much effort to rectify the situation.

 

[Linda in MN]

Lisak1- We cannot leave our waterfall running all winter, we have so much evaporation (or perhaps an undetected leak) that we've added a float valve to the skimmer box to refill the pond. The float valve is attached to a hose that is attached to our outside faucet and we have to disconnect it from the faucet when the temperature drops below freezing so we don't have pipes burst. And we have to net the pond, we have a lot of decidous trees that dump leaves all winter and we are constantly removing debris from the pond during the summer, especially after a storm. But I really hate trying to catch the fish in the fall and we always miss a couple that dart in between the rocks and hide from us so I wish I could leave them in the pond but I haven't figured out a feasible way to do that in our particular situation..

 

[Lisak1]

We had to add water to the pond twice this winter - my biggest concern about keeping the falls running. Luckily both times it was (relatively) warm. We have a short piece of hose that we keep for that purpose - we learned how not fun it is to deal with a long frozen hose early on! But you are right - keeping a hose attached to the house would cause issues.

How deep is your pond? This was the first year we ran the falls. We used a de-icer and air stone to keep a hole open in prior years and the fish were fine. But our pond is three plus feet deep.

 

[Linda in MN]

Lisak1- Our pond is only 24" deep at its deepest. There are many areas where it is less than 12" deep. What kind of de-icer did you run in previous years? I am considering leaving the fish in the pond next winter. We now own 3 heaters so we could put two out there and, if one died, we would still have a 2nd heater running. But I don't think I could use the bubbler and pump that I use in the garage.....

To all who responded: Here is what we did yesterday: We pumped the water from the pond and then filled the pond and pumped the water out 5 more times then refilled the pond and restarted it. We rinsed all the filter media thoroughly 3 times. I did not add any dechlorinator to the pond and earlier this afternoon it was still testing that it has a little chlorine in it. We have pulled the IonGen out for now, until the fish are acclimated and the string algae becomes a problem. Once the chlorine dissapates I am going to put activated carbon (inside media bags) in the stream that runs between the first and second waterfall. I have read that pesticides and herbicides should bind with the activated carbon but I don't want to "waste" the activated carbon having the chlorine bind to it. I have purchased 4 feeder goldfish (that are happily swimming in a bucket in the kitchen) because our local pet store only gets them in every two weeks and they got them in on Friday.. I am changing a little of their water every day since they don't have a filter. Once the activated carbon has been in the pond a few days I will acclimate the feeder goldfish and see how they tolerate the pond. The 10 fish in the stock tank seem to be doing well for now but, as the water temperature warms up, they will be too much load for the 100 gallon stock tank so we have to keep moving toward getting them in the pond.

I am hopeful at this point. I had forgotten that, when I called Preen Friday, the only thing the girl could suggest (before she told me to call the Product Safety Information Service) was to try activated charcoal. At the time I was thinking of that as something that is given in the ER for poisons and overdoses (I used to be an RN). But after I researched it, I think it might absorb any remaining toxins in the pond...