Pond Boss Forums GENERAL QUESTIONS Help Perch in my pond dying quickly

Hi all, Yesterday I started noticing my large perch 12" in my small 1/5 acre pond are all up at the edges of the pond and not moving very quickly, you almost can pick them up and last night 3 died. I have had this pond for 20 yrs. and not sure what the heck happened this week. What I can tell you is I started running my aeration bubbler about a month ago and only run it 2 hrs a day right now. I also had a lot of algae in my rock ledge so we I mixed a gallon of Cutrine plus and sprayed my pond with it and then ran my bubbler for about 24hrs to mix the pond up to get a good kill on the algae. I also added 4 large mouth bass to my pond this week which were about 10in in length. Do I have an oxygen problem or stress these fish out somehow. The perch just came off the spawn a couple weeks ago. Any help would be appreciated as these fish are dying fast. I actually know Bill Cody personally and hoping he will chime in. Thanks Todd

How much plant life died in a short period of time?

I have a small amount of algae growing in and around my rock ledge. It looks like i got a kill on the algae. I just got home from work and 3 more perch died, but the other perch are starting to be scared of me when I walk around the pond. I do also have a couple of Hybrid stripped bass in there and I haven't seen a problem with them. I think its an oxygen thing. Should I run my bubbler 24-7?

Hello-and welcome to PondBoss.
Not an expert here, but from what I've read, and remember from organic chemistry, you're almost certainly having a DO crash, and your most stressed fish, the large postspawn YP, are most vulnerable.
Your algae are dying, therefore not producing 02 and in fact consuming it as they degrade. Not sure about your Cutrine, but some copper products recommend only treating part of the pond at a go. Although completely logical and understandable ["Nontoxic to Fish!!"], you probably magnified the crash by running the aerator full bore to fully disseminate the cutrine.

So, in terms of recommendations--probably best to run the aerator all the time for now.

I'm with Yolk Sac. 99 percent of all fish kills are due to low D.O. However many times there are other factors that join together that cause a FUBAR. Sounds like you did such a good on the algae the decomposing algae is consuming oxygen, and/or your now 24/7 mixing of the water column is bringing up anoxic water. I don't know enough about the copper to know if you exceeded the lethal dose.

That said I'm not sure if there would be that much anoxic water on it's own this early in the year.

Can you get some kind of surface aeration going even if it's some kind if pump that pumps and splashes water onto the surface?

Todd:

How much planktonic algae was in the pond at the time of the application?

What PPM were you shooting for when you applied it? For algae treatments, you calculate the volume of water in the pond, then look at the label to see what the target PPM application rate is for that specific type of algae, then apply it. (a combination of Table 1 and Table 2)
http://www.archwaterworks.com/Docs/Surface/Labels/Cutrine-Plus.pdf

I would be running the aeration system 24/7 if you don't have a way to test the DO levels.

Are perch, 2 HSB, and 4 LMB the only fish species in the pond?? No minnows, grass carp, nor koi?

I started running the bubbler yesterday and today the perch are more active. its tuff to get close to them. thanks BILL, yes mainly perch and a couple of HSB, I did just put in 4 large mouth bass last week. I used to have Rock bass in the pond but they were to aggressive on our toes, so I think I have fished them out.I do have alot of minnows. I'm actually thinking on putting in some water lillies.

I think you also had some copper toxicity issues together with lower DO in the deep water with maybe some hydrogen sulfide from winter stratification that was brought to the surface with aeration. YP are three times more sensitive to copper than bass. If you are using blue dye this is hindering good natural dissolved oxygen production by the algae that you killed with copper based Cutrine application. Killing lots of algae with a well distributed / mixed dose of Curtine would lower the DO when all of it stopped making oxygen and started to die which also uses oxygen.

Bill Cody, I don't know how true this is, but I was told once to use your algae killer sprayer nozzle under water right on the algae. Of course not the whole pond at once.

What do you think?

I've been using some decendents (sp)of Rainmans blues. But they can't keep up with the Emilfoil.

Sorry I got off topic .

Hang-Loose you are correct - blue tilapia do not eat milfoil and then only maybe a little bit as a last resort. Application of algaecides is based on the type of algaecide and growth habit of the algae. It all depends.

Thank you Bill...I very much appreciate your knowledge and info.