Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Killing pond and starting over

Hi all,

I have a 3 acre pond at our family farm we have had some bad luck with on a few diff things and need to start over. It is over populated with dinky crappie and miniature bream with the bass non existent nearly now. That being said, I am planning to kill off the current fish and restock with minnows, bluegill, red ears and lmb. I am trying to figure out the best way to go about starting over. I have siphoned the pond down to about 1.5 acres of water with most of it being less than a ft and max 5ft and am ready to push the nuke button. Issue is, with what? I read about hydrated lime but was wondering other experiences or suggestions? I can't seem to locate rotenone and haven't located another option..

Thanks in advance.

Welcome to Pond Boss!!

I could be wrong, but I'm pretty sure you need a pond professional to use Rotenone. Hydrated lime you may be able to do yourself.

However, whichever course you choose, you want to make sure you get a full kill so going the professional route may have more value.

Does your pond fill from surface water flowing into the pond, or does it fill from groundwater? I ask because it would be nice to get the water level MUCH more reduced.

I am NOT a pond management expert, but this question comes up fairly frequently on the forum. I believe most of our actual management experts advise that you get the water to the absolute minimum amount. No matter what method you use as the "poison", if you have one tiny refuge of a little cove, area with heavy weeds, small basin of deeper water, etc. where your poison is not perfectly distributed, then a small population of crappie, green sunfish, or other unwanted fish could survive in that refuge.

If the experts advise more draining, then you may have to buy a 2" or 3" trash pump. Do you live at the pond location? If so, much easier to drain the pond, since you will have to "babysit" the pump a little, and also do gas tank refills.

It would be even better if there was one very low "sump" in your pond where all of the water drained. If you could get your suction hose into that area, then your fish kill plans would almost certainly be 100% successful on a nearly dry pond. If you don't have a sump, then a little work with a backhoe or mini-excavator might really help (if available).

At this point, patience and doing it right to get a 100% kill rate is much more valuable than doing it quickly.

Good luck on restoring a 3-acre family pond. Down in Alabama, your new fish will grow very rapidly once you get them into a "nice home"!

Need to understand where the crappie are from. Were they stocked or did they just appear?

https://www.zoecon.com/all-products/fish-management/rotenone-powder-fish-toxicant

https://www.boatcycle.com/catalog/p...neral-farm-chemicals/rotenone-5-solution

RESTRICTED - Requires application number for all states

Rotenone is expensive, which is another reason to not do a renovation unless it is necessary. Costs can range from $50 to $80 per gallon. At $70 per gallon, the 5-acre pond above would cost $70 X 20 acre-feet = $1,400. Prices vary from year to year and depend on total amount purchased. So says Google.

At $1875.00 plus application fees, makes me think that the trash pump & hydrated lime might be an option. I would contact & talk with a local pond management professional. I am cheap & lazy, I don't want to spend more or work more than I have too; but I want it right the first time!

Rotenone poisoning can be fatal and there is no antidote. Mechanistically, rotenone inhibits mitochondrial complex I, leading to reduced ATP production, compensatory glycolytic upregulation and secondary lactate production, and oxidative stress.

I did this very thing 18 months ago.
First get a hold of a licensed pond management professional and go over your options.
Rotenone is going to cost you about $150 an acre foot. Well worth it IMO. (If anyyone can still get a hold of it )
Best investment I ever made.
18 months post kill and I have the start of a great fishery

Put 10 in there after a day at the lake. 20 years later we wont do it again. Had a great time filling buckets with them for years but a man cant keep up.

It does fill from surface water. I actually started looking at the means to draw it down further with a pump after i posted that. My siphon only allowed me to reduce the water by 2ft overall, believe you are on the right path.

Rotenone is a Federally restricted-use piscicide (pesticide for killing fish) and therefore requires a pesticide applicators license - at the very least - in all US states.
Liquid rotenone is currently not in production (for the past 18 months) and won't become available again until sometime in late 2025 - supposedly.
Greg Grimes (in GA) probably has some liquid rotenone remaining; otherwise, only powered rotenone is currently available - and only in 110 lb kegs. Btw, liquid rotenone - when it was available - was well over $120/gal in bulk.
A typical average rate for powdered rotenone is 8 lbs/ac-ft (= 1 gal/ac-ft of the liquid).
IMO, rotenone is "safer" to apply (with appropriate PPE) than hydrated lime - which is extremely caustic - but neither product is pleasant to handle.

Thanks for those details! I didnt know the app rate. I have an applicators license so took that issue off the table but ran into the 2025 estimated time frame for the liquid.

I have a trash pump lined up for this weekend and will run it around the clock. What is the application rate for Hydrated lime? Sounds like my best option and easiest.

I have always wondered what pool chlorine tabs would do, I heard a story about a few neighbors that were feuding over some kind of control over a shared body of water and the one guy dumped a bucket full of pool chlorination tabs in the water and killed every fish in it.
May be a wives tale but they don't survive in chlorinated water, no? and the chlorine would dissipate with time, no?

Ive been contemplating trying it on a little pond here local that is overpopulated with bullheads, the owner doesn't care what gets done with it, we been going there and catching a bunch of the little bullheads for trot-line baits, but they are damn near too stunted for that, or at least we'd love if they were about twice as big as they are now.
Just thinking out loud here.

As noted above - get the water level as low as possible preferably to the lowest pool and smallest possible and then ACCURATELY calculate the gallons in the remaining water volume. The smaller the final volume the better the chance of a 100% kill.

Here are important notes from the prior PBoss Forum discussion of killing a pond with green sunfish. The PB member wanted to use copper sulfate to kill the pond. IMO - THIS IS A BAD IDEA.
Forum Thread Discussion:
Cody - I agree with FishinRod's notes above. NO matter what you are doing do your GOOD homework.
Also CuSO4 will not reduce the DO in the pond water. Any loss of DO from CuSO4 was due to decay of the dead material. The decay process consumes the dissolved oxygen. Besides GSF are very tolerant of very low DO. Darn things if kept damp can live out of water for over 15-20 min and still live. Copper is a toxin that kills the fish,,,, it does not directly affect the DO. Copper that would be added will never leave the sediments and remain there as a potential problem until the pond sediment is removed. Cu is stable in the environment as copper bound substances; does not rot nor deteriorate. Also alkalinity of the water determines the reactivity and killing ability of dosage of CuSO4. Different species of fish have different tolerances to copper in the water. Trout most sensitive and bass most tolerant. All other species in-between the low and high doses.

Because you are wanting to do this fish kill now this Fall and rotenone is out of common stock until hopefully some time in 2025; here is part of a PBoss forum discussion from Sept, Oct, Nov 2024 where the pond owner (BreamAngler) wanted to kill the entire pond due to infestation of green sunfish. The pond owner never returned to tell the method he used and the results of treatment. When killing a pond you never know the true results of the fish kill until 1 to 3 years later when any remaining unwanted fish have had a chance to spawn and repopulate the newly stocked pond. This is why it is VERY important to do the kill process / method VERY CORRECTLY. Careless errors result in having to do the whole thing again.

Another treatment the US Fish & Wildlife Fish Hatchery Management (5th Printing 1992, 2012) book says one can kill fish and disinfect and kill "wild" fish in the hatchery pond besides using rotenone and Antimycin is to use Chlorine in the form of HTH at a concentration of 5ppm. Important make sure what chlorine you use is the right stuff and dilutes to the final concentration in the pond to the 5 ppm concentration. You may need help from some sort of chemist or professional applicator for this. IMO I would use a higher concentration of 6ppm AND make sure the entire pond volume gets the 6ppm dosage. They say chlorine kills most wild species of fish. NOTE use of chlorine will disinfect the entire pond basically eliminating all the basal plant algae and animal productivity wherever the elevated chlorine concentration infiltrates. This is why about all municipal water treatment plants use EPA approved chlorine concentrations to disinfect water for public use. Low doses of chlorine also kill viruses, bacterial and microscopic organisms for public domestic water uses. In my professional experience and opinion there are better, safer, and less harmful more environmentally better ways to kill fish in a pond than to use chlorine. These reasons are why only a very minimal amount of water should remain in the pond prior to a chlorine treatment so there is less harmful impact for the long term pond health of the pond ecosystem. .

IMO the chlorine dosage eliminates the entire food web of the pond. IMO before restocking after a chlorine treatment, I would allow the pond time, as in several months to year, to have all the basic bottom of the pond food web time to reestablish itself so there are recolonized algae, zooplankton and invertebrates (bug larvae) present to feed newly stocked fish. Chlorine does what it does, it kills (poisons) all life forms. It is not wise to restock fish into a disinfected pond with no food web or bottom of the food chain to feed the fish. One might need to restock some phytoplankton and zooplankton from another healthy pond after dosing a pond with chlorine.

If you don't do everything correctly,,,,, all your time, effort, and money are wasted and you will likely have to do it all over again. They (Fish Hatchery Mgmt Book) claim chlorine deteriorates fairly rapidly (1-2days) and looses toxicity after several days to a week depending on pond conditions. However chlorine as it reacts in the natural water, it does form various residual chemical byproducts; some of them are considered stable in the ecosystem and as human health concerns. These are important reasons for applying chlorine to only a MINIMAL amount of the pond volume. Do your homework before using chlorine as a pond treatment. Water after treatment should be tested to see if fish survive before restocking by holding live fish in a minnow bucket or mesh container placed in the pond for several days.

Be forewarned. NO matter what method you use it is SMARTEST to LOWER the pond level as much as possible so you:

1. don't need as much chemical

2. make sure all fish are forced out of all shallow shoreline areas into the deeper basin. GSF are very tolerant and famous for hiding in shallow shore nooks and crannies to escape harsh conditions. Force them out of the shallows into the bottom shallow bowl of the pond and no place to hide.

3. insure to fully circulate all the remaining water (pumping or aeration) so all depth areas get the full concentration or dosage of what ever chemical you use.

4. IMO you want only a small amount of the pond basin area and volume that receives the killing chemical. This causes minimal contamination of the pond basin.

BreamAngler Says - Thanks, I'm very familiar with calcium hypochlorite (pool shock). I use Chlorine to sterilize rainwater runoff tanks that collect from my gutters @ 1ppm.

For 24 bags, it would treat 240,000 gallons @ 5-10ppm and I could draw the pond down to about XXXX gallons for good measure ..... and cause less impact of the chemical on the pond basin.

https://www.amazon.com/DryTec-Hypoc...p;hvtargid=pla-4583726554502642&th=1


Cody - When you use / apply the granular calcium hypoclorite does it need to be dissolved first? If you just toss in the granular and it sinks how do you know it gets distributed throughout the remaining pond bottom that has water. Do you have a way to circulate the pond water after applying the calcium hypoclorite to insure good distribution of chlorine? NOTE use of chlorine will disinfect the entire pond eliminating all the basal plant and animal productivity whereas rotenone basically affects gill breathing animals and some invertebrates depending on concentration used.

Whatever method that you use,, I would first test the concentration that you plan to use to verify that it kills several GSF that you have in a tank or tub of known water volume and measured or tested chlorine concentration. Get a chlorine pool water or similar test kit.

BreamAngler - When using calcium hypoclorite for water tanks, I shake up measured granules in a one gallon water jug 1st, then pour mixture into tank after it's dissolved. This step isn't necessary for pool owners since they have pumps/circulation. For this pond application, I will probably setup trash pump intake close to the bank and pour chlorine mixture on top of pump strainer and direct outflow towards the middle of the pond.

Great idea on the test kill. I'll bait a minnow trap with bread and see how tough they are before wasting bulk chlorine.

https://www.cleanwaterstore.com/res...to-add-to-storage-tank-to-kill-bacteria/


FishinRod - I have read about some fish kill treatments not being successful, and thought: "How hard can it be to mix your chemicals to the proper concentration?"
However, after I read Bill's post above, and realized that the chemical must be perfectly distributed. Only then, did the little light bulb go on over my head.
Originally Posted by Bill Cody
GSF are very tolerant and famous for hiding in shallow shore nooks and crannies to escape harsh conditions. Force them out of the shallows into the bottom bowl of the pond and no place to hide. Fully circulate all the remaining water (pumping or aeration) so all depth areas get the full concentration or dosage of what ever chemical you use.
I think he is worried about you not getting a toxic level of chemical to every GSF's hiding place.

Correct me if I’m wrong, but chlorine being a very strong oxidizer will break down quickly and react with any organic matter. If the pond basin is thick muck, it is questionable how long the active chlorine will last to provide a lethal dose to the fish. I would suspect you will need to apply a lot more chlorine than just what it takes to get just the water up to the lethal level. I would also suspect you wouldn’t want to be anywhere near the treated pond for a few days to avoid the out gassing which is going to be quite unpleasant, if not caustic to your lungs and nose.

If you manage to drain the pond sufficiently, think of the treated area as a burn scar, as that is what it is. But the banks of the pond that are untreated should still hold plenty of organisms to seed the pond fairly quickly when it refills. Just treat it like a freshly dug pond, starting with a forage base the first year.

liquidsquid - makes good insightful comments about the negative features of using chlorine in ponds. I agree with his comments, it is not a good idea and his comments. I would only use a chlorine based treatment as a very last resort and only in a minimal amount of water volume. Remove as much water as possible before any fish kill treatment. No matter what fish kill method is used, the best practice IMO would be to first dewater the pond so the cost is less and there is minimal impact on the pond ecosystem. Plus with minimal water in the pond, the pond water quality will recover much quicker for a restocking of fish. Remember you will want the pond to be as healthy as possible with low chemical residual and less long term impact after the fish are kill.

This implies that there is a chemical residue after treatment! I don't recall a Pond Boss discussion where we considered that.

I just checked the Wiki (I know) page for rotenone. Apparently the residual rotenone clears more quickly from rivers than it does from ponds or lakes.

I assume this indicates, that in static water, the chemical degradation rate is significantly lower and/or the lack of dilution allows the chemical to remain dangerous to fish for a much longer time in ponds.

Conclusions:

1.) If you pull the pond volume down by 90% and treat with rotenone at the prescribed concentration, then when the pond is full - the remaining chemical is at a minimum of 9 times more diluted than the effective dose. It should then be safe if your initial treatment was performed at the correct concentration?

2.) Do not lose patience if your pond is slow to refill due to low rainfall conditions. If you stock your fish "early" while the pond has barely enough water for the stocked species, there is a chance the fish could be subject to a significant concentration of rotenone.


Question:

If your stocking plan is time dependent (aren't they all?), is there an inexpensive "indicator" fish we can use to test for safe water conditions?

Reading some studies, it looks like rainbow trout and yellow perch are the most sensitive of our common fish. Mosquitofish might survive at 15x the lethal dose compared to sensitive fish. (I wish that was reversed!)


Bill Cody (and others),

Please feel free to correct or clarify anything in my "conclusions" or answer any questions that it raises relative to your experience.

On this note. When Rotenone was applied to my pond, The water volume was down Approximately 60%. We applied chemical for 12 acre feet. Luckily we have a fairly large well to refill the pond,
24 hours after application the well was started, 5 days later (6.5 acre feet) of water was put into the pond. The following day test fish were put in, They survived over a 24 hour period, The following day 100# of FHM were stocked.
I know we sped up the natural process of filling the pond but this tells me Rotenone is not lethal for very long
If you can go from application to reintroduction in a 6 day period while only increasing water volume 33% it can't have that long of a lasting effect

You can also neutralize the Rotenone with Potassium permanganate.

Yes - It should then be safe if your initial treatment was performed at the correct concentration of usually 1 to 2 ppm all depending on pond conditions and specie of fish to be killed. Diluting the standard rotenone by 3X-9X of the final pond volume treatment concentration after the fish kill, lowers the final application concentration. Even a 3X dilution is evidently enough to allow the usual restocking fish species to survive as noted by the experience by JasonD. This assumes the rotenone kill concentration was 2ppm or lower. Jason did not provide the kill concentration of rotenone that was applied to kill fish.

Question was : If your stocking plan is time dependent (aren't they all?), is there an inexpensive "indicator" fish we can use to test for safe water conditions?
IMO common indicator fish can be bluegill, sub-adult bass, crappie. fathead minnow, pet shop guppies or goldfish.


Not always a true statement. The rotenone noted by JasonD was later diluted to a non lethal concentration, however this does not mean the rotenone kill concentration is not lethal for longer periods in the original treated pond volume. At least Four (4) main things cause rotenone to lose it's potency: 1.dilution, 2. sunlight exposure , 3. temperature and 4. amount or density and type of suspended particulates in the water column. Rotenone kill concentration decomposes faster the warmer the water and in more sunny conditions. Rotenone applied during cool or cold water and lengthy cloudy days can have kill effectiveness for numerous weeks or a couple of months. Some water conditions and certain species of fish require a higher concentration of rotenone. It all depends. This is why one should have good experience and knowledge when using rotenone which is partly why a pesticide license is required for its purchase.

Bill Cody,
3ppm or 1 gallon per acre ft

Was used to kill CC, common carp and gizzard shad. We were not aware of the gizzard shad. A few LMB, white crappie and flathead catfish also popped up
Application was done the first of May, not sure of water temperature
Water was extremely Turbid, less than 2” of visibility
Goldfish were used 5 days after application to make sure the water was safe for the first round of stocking

One thing that never gets talked about
What to do with all the fish afterwards ??
We let them decompose, there were no sign of them within 3-4 weeks
Looking back I would have tried to manually remove as many as possible, kind of difficult with 6000 lbs though
It created a serious nutrient overload, I should have at least applied a beneficial bacteria of some sort, to this day, 18 months later I’m still fighting the nutrient issue.

Remove as many dead fish as possible;; no matter how much work it takes because the nutrient release and nutrient recycling will fertilize the pond system from 6,000 lbs of dead fish so close to 10,000 to 20,000 lbs or more of weeds and algae will be stimulated and grow. Dealing with this plant problem will be more costly than removing 6,000lbs of dead fish. Removing the dead fish is very beneficial because it slows the aging process of the pond system. Harvest of fish or plants always removes accumulated nutrients that are long term a big cause of more plant problems and muck accumulation (pond aging).

The fish that were killed had accumulated in their biomass lots of all the nutrients that are necessary for plant and animal growth which is why allowing them to die back into the pond will fertilize the pond with a surge of nutrient fertilizer as the fish decompose. Removing the dead fish actually sets the pond aging process back toward cleaner nutrient conditions which would have been a very BIG benefit to slowing the aging (eutrophication) of the pond. IMO a mistake for not doing it,

For a better idea of how much nitrogen(N) and phosphorus(P) fertility was in 6000 lbs of dead fish according to a prior PBoss thread this amounted to 147lbs of P and 678 lb of N. That is a lot of fertilizer to be putting into a pond of 12 ac ft. Expect to see lots of green growth in the next few years as the pond ecosystem responds to all the released nutrients. It is said that one pound of phosphorus will grow 500lbs of algae thus the 147 lbs of P could produce 73,500 lb of algae = 36.7 tons.

https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=540041

Exactly why I posted that little bit about removing the fish.
Lesson learned, too late to do it differently , I’m dealing with it now,
Fish are growing very well but so is everything else. Not only algae but various different plants and weeds.
Summer/Fall of ‘23 was a bunch of filamentous algae and plant growth.
‘24 was a whole new batch of weeds and Cyanobacteria
Seems never ending

When it is over fertilized it will grow over abundantly. It is nature's way of doing things.

Hello all, back for an update. I rented a 4in trash pump and let it rock for 15 hours while i could be there to babysit the gas tank. That drew it down another 12inches and decreased the surface area a large amount since i have a big shallow area.. I also ordered a pallet of hydrated lime and it came in today. I am planning to go out this week and ending all inhabitants. My plan is to put a trash can in the boat and two small pumps, one to pump in and one out of the can to create the slurry with.

Any other suggestions or food for thought would be great. Thank you all!

Anyone with great ideas on how to apply the lime? Im starting to second guess my garbage can and 1inch pump for a slurry idea