Pond Boss
Posted By: cokeman Fish Kill - 08/15/08 12:25 AM
All of my fish have died. Eight weeks ago I had a very bad case of algae over half of my pond. I sprayed cutrine on it, put up a windmill areator, and put aquashade in my pond, all in the same weekend. Last weekend fish were feeding like crazy. Two days later they would not eat at all. Two days after that they were all floating belly up. I had three days of cloud cover and warm temps. I am assuming between the clouds, warm temps, and algea dying, I had a D.O. crash, causing my fish to die. My question is how do I know when it is safe to start restocking my pond? I do not want to stock fish if there is not enough oxygen in my pond to keep them alive. I know I can buy a D.O. meter but I really don't want to spend 400 dollars on one. Can anyone offer any other suggestions? Thanks in advance for any replies.

Posted By: burgermeister Re: Fish Kill - 08/15/08 01:45 AM
stocked in the fall with fingerlings, no need to worry about O2 levels. BTW, what type and size fish died, and what are you planning on re-stocking?
Posted By: Theo Gallus Re: Fish Kill - 08/15/08 01:57 AM
Welcome to the forum, cokeman. I wish it was under better circumstances.

Any aeration? I'd put the price of an O2 meter towards an aeration system.
Posted By: cokeman Re: Fish Kill - 08/15/08 01:58 AM
I had 700 catfish that were stocked this spring. They were 4-6 inches when stocked. They were 10-12 inches when they died. I also had five grass carp that had grown to 20 inches. I also stocked 40 pounds of fat head minnows. I was going to stock 500 bluegill this fall and 150 bass next spring. Not sure what I should do now.
Posted By: cokeman Re: Fish Kill - 08/15/08 02:01 AM
Theo, Yes I have a windmill aerator with two diffusers.
Posted By: ewest Re: Fish Kill - 08/15/08 02:19 AM
What size pond ? Cu killed the algae and the plankton and the dye stopped any new or remaining plankton from getting the light needed to power photosynthesis and produce O2 plus the dead algae used up what little O2 that was left. Did the event kill the FH ? If so you probably had a complete O2 depletion as they can tolerate low O2.

Wait until the Cu and dye are gone from the system (a mth) and then try a few FH. If they do ok for a few days then you can stock other fish.
Posted By: cokeman Re: Fish Kill - 08/15/08 02:34 AM
ewest, Pond is 1.5 acres. I think all FH died too, as I have not seen any. When I had the algae problem, should I have not used the aquashade and just used the CU. I am trying to figure out what I did wrong so I don't do it again
Posted By: ewest Re: Fish Kill - 08/15/08 02:49 AM
The 2 together can be a lethal killer. Also in low alkalinity water Cu products can inhibit fish gill function. Gill problems do not happen nearly as much with chelated copper products vs CuSO4.

One rule of thumb is to never treat more than 20% of a pond in one application. I try to stay around 10%. Also treat the problems early when the water is cooler as the water holds O2 better when a little cooler. I try to treat FA early when it is on the pond bottom because you are not as likely to kill the top 3 feet of the water (including surface plankton).
Posted By: Shawn Banks Re: Fish Kill - 08/15/08 03:49 PM

I'm thinking that the main culprit was too many fish. 700 10-12" channel catfish is a lot of oxygen demand. Given that your algae treatment was 8 weeks ago, the copper should have been long gone. Even though you suppressed new planktonic algae growth with dyes (and therefore oxygen production), you were playing with fire by having so many catfish that you were feeding. Although windmill aeration is not the best solution, you got some benefits, but it just prolonged the ineveitable.

It's easy to get gung-ho with a pond and stock fish at rates that approximate what could be found in hatchery grow-out ponds. Hatcheries, however, often have fresh water pumped through routinely or have high oxygen surface agitators.

When you push the envelope with too many fish, bad things can happen. Sure, killing too many plants at once can cause oxygen squeezes, but you were 8 weeks post treatment. My advice is to saddle-up again but reduce the amount of catfish you stock and come up with a feeding regime that is safe. As you know, fish are like us in terms of cellular respiration. The more you feed, the faster they grow and metabolic rates increase. This all requires oxygen.

Good luck.
Posted By: jeffhasapond Re: Fish Kill - 08/15/08 04:12 PM
Cokeman, I'm sorry to hear about your fish kill.

Welcome to Pond Boss. You are already getting good advice. Continue posting pond questions, comments and photos if you have them. One great thing about this site is that you have access to the best pond minds in existence.

We are all one big, mostly happy family (some a little too happy if ya get my drift) that like to help each other out.

We're glad you found us.
Posted By: Ric Swaim Re: Fish Kill - 08/15/08 07:30 PM
How much aeration does your windmill produce? If you have enough wind & you didn't start it up in short increments that also added to low DO in the pond.
Posted By: cokeman Re: Fish Kill - 08/16/08 03:39 AM
Shawn, I was just using the recomended fish stocking rates from my local fish farm. They recomend 700 catfish, 500 bluegill, and 200 bass per acre if you are going to feed your fish. Please let me know what you think I should stock in my 1.5 acre pond.

Thanks, Cokeman
Posted By: cokeman Re: Fish Kill - 08/16/08 03:50 AM
Ric, My windmill produces 3 to 6 cfm depending on wind speed. I started it up in short increments, before I finnaly started running it 24/7.

Thanks, Cokeman
Posted By: Theo Gallus Re: Fish Kill - 08/16/08 11:02 AM
 Originally Posted By: cokeman
Shawn, I was just using the recomended fish stocking rates from my local fish farm. They recomend 700 catfish, 500 bluegill, and 200 bass per acre if you are going to feed your fish. Please let me know what you think I should stock in my 1.5 acre pond.

Thanks, Cokeman

For starters, knock it down to maybe 100 cats. After that, tailor for your goals.

500:200 BG:LMB is not a bad ratio if you want to be bass heavy and manage for large BG. If you want large bass 1000:100 is more in line.
Posted By: ewest Re: Fish Kill - 08/16/08 01:37 PM
Yes that would be to many CC for BOD and carrying capacity when grown (2 lbs). At 1/2 lb each and 10 inches they should not have been the cause. The CC plus the FH would only be about only about 400 lbs per acre and with aeration should be no problem. The growing O2 demand by the CC plus reduced O2 production from plankton elimination in conjunction with the big BOD increase from dead plankton and FA is the likely cause.

One positive note - your pond has indicated its max productivity (carrying capacity) as currently configured at my guess 400 lbs of fish per acre. Stock the pond so that you meet your goals at under 400 lbs per acre when the fish are grown. As Shawn notes if you try to get to close to max lbs you greatly increase the risks of problems.
Posted By: Shawn Banks Re: Fish Kill - 08/16/08 09:02 PM

I run into this all of the time. Some fish hatcheries are more interested in selling you more fish than you need because they want to sell fish. You can look at the reason for the fish kill from different perspectives, but had you had fewer fish (lower oxygen consumption) it probably wouldn't have occurred- more on this later. Ultimately, oxygen consumption exceeded production. The dyes you used also inhibited production of oxygen from phytoplankton. Ewest, I politely disagree with you but the chemical application made two months ago probably had little influence. I say this for two reasons, 1) it was two months ago, 2) copper concentrations and the ability to kill perish quickly in our hard waters of the midwest. Also, filamentous algae doesn't have a lot of biomass associated with it (i.e. you can kill a lot more suface area of filamentous algae in one shot than you can a submerged plant). I would refrain from using dyes, though. If you really want to grow some fish and ensure some good "free" oxygen from phytoplankton then I would cut back on the dye. See how you can look at this from two ways??? if you had fewer fish then less consumption or had no dye then more production from phytoplankton. The bottom line is that the conditions were just right to cause disaster. From my expereince, a stocking rate of 467 catfish/acre (you had 700 in a 1.5 acre pond) that are getting fed regularly is a HUGE risk for a midwestern farm pond unless special circumstances apply (water exchange system, high oxygen agitator- more on this later). This is especially true in the heat of the summer.

I would also predict that your fish were weighing between 3/4 and 1 lb given the 10-12" size class of feed trained catfish. This really boosts you're biomass. In the midwest, most ponds support and we are safe at 250lbs of fish per acre and should not exceed 400lbs without some serious aeration (for farm pond fisheries). I'm a huge fan of bottom diffusion aeration, but it is not near enough for heavy feeding operations with lots of fish/acre. I'm not even going to pretend to know how much you were feeding but I am not surprised that you had a kill even with the windmill diffuser. Aeration has its place, I use it all of the time (electric units), but it is false security for guys trying to grow big fish in small ponds with agressive feeding regimes. Just read some posts on this site. The best pondmeisters this website has (probably in the nation) have gotten burned from oxygen related issues. Sometimes the kills can't be prevented, but you can stack the odds in your favor. Surface agitators are the only way to go if you really want to push the carrying capacity envelope. You can do more than normal with a bottom diffuser, but you can do a lot more than normal with a surface agitator. Most of my clients have bottom diffusers and feed lightly-moderately. The guys who feed pretty heavy have surface agitators- sometimes with diffusers.

The fact is that shallow heavily vegetated ponds are more susceptible to fish kills. It's also a fact that ponds with lots of fish that are fed regularly are also more susceptible.....just read some of the posts on this site. This is not to disuade from feeding, but guys who feed a farm pond like it was a hatchery pond will almost always pay the price.

I'm sure lots will disagree with me on my last comment, but I contend that some people forget what "supplemental" feeding really means. It's easy to do. It's easy to get excited and want to feed more and more and more. Just be careful. Remember, these are farm ponds not fish hatcheries.

Also, our BOD in the Midwest can be naturally high because of the fertile nature of our soils and the agricultural use of many of our watersheds. If you are going to feed your catfish regularly and have other fish species, I would stock no more than 200 CCF/acre. I really like to see 50-100 CCF/acre, though. This is especially true if you also desire a decent bass fishery. Don't forget about harvest!!

I certainly agree with Ewest in that you found your limit. Ewest also made a great point that a lot of people forget about.....think about the pond when the fish are grown. Feed your fish and have fun. Be sure to cut things back in the heat of the summer. Remember, warmer water cannot hold as much oxygen as cooler water. Also, the gross oxygen consumption inceases as fish get bigger. For example, (hypothetical numbers) catfish-X uses 5 ml of oxygen per hour, another fish (catfish-Y) is 1/10th of Catfish X's size and uses 2.5 ml per hour. The oxygen consumption/demand is greater for the smaller fish (amount of oxygen consumed per unit body weight) but the gross amount of oxygen being used from the water is higher for larger fish.
Posted By: Greg Grimes Re: Fish Kill - 08/16/08 10:32 PM
Cokeman I will make a suggestion, see how much it would cost to get Shawn to evualate your pond. You will save money in the long run with a proeprly designed water quality and fish stocking plan.
Posted By: Rainman Re: Fish Kill - 08/20/08 02:05 PM
 Originally Posted By: cokeman
Shawn, I was just using the recomended fish stocking rates from my local fish farm. They recomend 700 catfish, 500 bluegill, and 200 bass per acre if you are going to feed your fish. Please let me know what you think I should stock in my 1.5 acre pond.

Thanks, Cokeman

700 Catfish???!!! Sounds like that hatchery wants to move some CC!!! I've NEVER heard of a rate that high.
Posted By: Scott Trava Re: Fish Kill - 08/21/08 12:13 AM
how could you manage that load of fish in a 1 acre pond unbelievable. Take away 1200 fish and install lower chain and enjoy your pond
good luck
Posted By: cokeman Re: Fish Kill - 08/24/08 01:03 AM
Stocked 2000 FH today to see how they would do. All were dead within five hours. I thought my pond would have recovered from oxygen depletion by now. Guess I was wrong again!
Posted By: ewest Re: Fish Kill - 08/24/08 02:13 AM
Please describe your water now. You should not still be in a DO problem at this point. Something is causing an ongoing problem.

So much for only waiting a week.
Posted By: cokeman Re: Fish Kill - 08/24/08 02:24 AM
Water is greenish brown. I can see about 12 inches down. Have some aquatic growth, which looks like long strands of grass just under the surface. When I disturb the ground on the pond bank, there is a lot of black goop under neath. I don't know if this normal.
Posted By: Shawn Banks Re: Fish Kill - 08/24/08 02:52 AM

Can you provide us with a little more info about the fatheads you stocked? Specifically, how were they transported (in bags, fish truck, in a cooler)? How long was the tranport? Was oxygen on them while they were transported? Any idea of water temps in the transportation water versus the pond water?

This is a tough time of year to be stocking fish because of the water temps. Just trying to rule out transporting and stocking variables as the cause of death for the fatheads. It would be easy (and probably correct) to assume the same conditions last week killed the new fish this week. However, let's play it safe and rule out the stocking/transporting variables. Also, were you able to remove any of the dead fish from the original kill a week ago or does the pond have rotting carcasses all over the place.

I'm with Ewest in that I would have assumed your DO problem would have already been resolved. Perhaps the stocking info will help us. If not, then it is still possible there are oxygen problems or something bigger going on. Lastly, were you ever able to observe the fish as they were dying? If so, what did you observe (erratic swimming, piping at the surface, spontaneous combustion, etc)?
Posted By: cokeman Re: Fish Kill - 08/24/08 03:11 AM
FH were transported in bags filled with oxygen. Time to transport was 1.5 hours. When I got to the pond I put the bags in the pond for 15 minutes before I set them free. I have no idea what the temps were. All of the dead fish from last week have been removed. When FH were released most of them swam away, while some just set in the grass. Within 30 minutes they were swimming along the edges of the pond all the way around. At that time I thought everything was OK, so I left and came back five hours later and they were all dead around the whole pond.
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