Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Cutrine Plus is killing catfish

Hello Everyone,

I’m making this post for my parents, instead of myself. I’m really hoping someone may be able to help them out. Since I’m making this post for them, I apologize if I use the incorrect terms or words, or don’t know the specific details. I can ask them for more details if you need it.

My parents own a pay lake that is approximately one acre if I were to guess. They keep it stocked with catfish for all the fishermen. They noticed that they were getting more and more algae on top of the water. I’m assuming it’s algae, I live out of the country at the moment so didn’t see it.To try and fix this, my dad used Cutrine Plus to attempt and get rid of the algae.

They added Cutrin Plus almost two weeks ago and fish have been dying. My mom said yesterday they picked up 200 dead catfish. She said they see the fish near the banks at the surface.

Does anyone have any idea of what might have caused this and most of all how to fix it??

Not only are they losing the fish they stocked it with but the lake is now closed until they can fix it. Thanks in advance!

It's possible that too much of the pond was treated at once causing a massive die-off of the algae. The decay of the dead algae uses up the dissolved oxygen which the fish need to breath.

Did they treat the whole pond at once? I've never used herbicides in my pond, but most recommend treating small portions at a time to avoid killing the algae all at once causing an oxygen crash.

Remove the dead fish and as much of the algae as possible. Do you have means of aerating the pond?

Sorry for the pond problems, but welcome to the forums, you have come to the right place for advise.

My first thought is they may have used it on too large a portion of the algae. This will cause a large die off of the algae, which in return will cause a o2 crash as the algae breaks down. I would put in any emergency aeration you have and if possible manually remove dying algae and fish.

Thank you for the response.

I just spoke with them over the phone. They said they did one half the pond and then the other half, although I’m not sure how much time in between. They also believe they did too much of the pond at a time.

They said they are aerating it now and are waiting for another one to come in soon.

They stated they concerned now with the water being stagnant and the fish getting sores.

Is aerating it about all they can do at this point?

Thank you again for the help as this is there business and I hate to see them taking this hit.

Starting an aeration system up too fast can cause problems too. It brings up alot of "bad water" too quickly. And, running one that is undersized can have issues. If it cannot sufficiently aerate all the water...it just keeps bringing bad water up into the good water.

Don't automatically assume fish are dying just because of an algae treatment in a pay lake. The herbicide is not the issue, but as discussed above, protocol may be the issue. But, when lots of catfish are stacked into a small pond, water quality is the number one issue. When fish are stocked from the source, they are losing weight, so most pay lake owners feed the fish to help maintain and gain weight so they don't lose money from weight loss. Catfish typically lose 1-2% of their body weight per day when in transport or stocked heavily without food. Feeding mitigates those losses and adds to the bottom line. Pay lakes feed the least expensive feed as possible, meaning conversion rates are around 2:1, maybe less. That means for every pound of feed fed to the fish, half goes into weight gain, half into waste. The pond must process that waste. It does it by converting to nutrients that something else takes up...such as algae, or blue-greens, or some other plant. Some of the waste break down adds toxic gases and some solids to the water, from the bottom up. Some of the waste waits its turn to be processed. If waste is added faster than the pond can process it, the water becomes toxic from the bottom up. When that toxic layer rises high enough, fish are breathing their own waste. Add in an algae treatment and that chain of events can be expedited.

My bet is a combination of things have happened to cause a correction...in this case a fish kill. Aeration is necessary. If this pay lake has a secondary source of water as most of them do, it's past time to change some water.