Sad but true. In a effort to control some of the algae in a small pond (4'X30'X50') I put some barley pellets in. Well, I probably over did it. A few days later we had 90* weather and no floating FA. There still seems to be some live Chara at the bottom though.

A couple days later it started to smell and the BG, LM and channels were struggling. It's been a few days of that, lost the big LM, both channels and about 50 small BG. I've added all the fresh water I can (without draining) and have had the aerator on/off wondering which is better.

What is the general consensus? Continue aeration or turn it off and hope for the best?

Fortunately I wasn't so careless in the larger pond with the big fish. I hope I learned my lesson.

sad days there tecman, sorry for the loss. i have not yet experienced a fish kill.

here's my 2c FWIW, i hope others chime in. it sounds like the death and decay of plant material has driven oxygen demand over the top to the point the fish are suffocating. if this assumption is correct and you've had the aerator off for a while, it seems to me it would be dangersous to turn it on and run for a long time. you might have "dead" water that needs a gradual replenishment of O2. if this seems like the case, i would suggest a gradual step program, run aerator for 15 minutes first day, 1/2 hour the next, 1 hour the next, then 2 hour, 4 hours, 8 hours....until you can run full time.

in my pond i have kept aeration going on 8 to 10 hour shifts for over a month now. i first started during the day to help warm the water a bit, get a phyto bloom going, and get the fish active. with the warmer weather i've since gone to a summer patter (night time only). this has managed to keep the visibility down and limit the weed growth.

good luck,

Thanks for the advice Dave. Sounds like a good plan. I should add that since I installed the aeration 2 years ago and run it 24/7, I have never had a "bloom" even in this Central Coast California sun. I suspect that is likely due to the abundance of Chara. My ponds are loaded with the stuff. Generally that is not a problem until some of the FA creeps in, then it gets messy. Thats why I was trying to find a little balance using the barley pellets in the small pond.

I have left the aeration off all day and the small BG don't seem to be gasping quite as much. Maybe just wishful thinking.

think about this too tecman, is the fresh water you are adding aerated? typical "fresh" well water (if there is such a thing) has almost no O2 in it and needs aeration before adding to a pond.

The veracity of this statement is inversely related to the size of the pond.

All of the studies I have seen indicate that barley straw takes a while to work by decay. I don't know about pellets. I doubt it is that aspect that is the problem. Could be just a DO problem or something else entirely like some other substance in the pellets or elsewhere. If you have fish of different sizes and types dieing I would not wait around to long. I would move the aeration shallow and turn it up and aerate the well water somehow.

The well water is aerated through a venturi but it is on the bottom of the pond. The last couple days I have added water by attaching a nozzle to a hose and spraying it across the surface. Kind of a non issue now since the pond is full.

Ewest:
I hadn't thought of moving the aeration shallow. I will do that tonight. The reason I thought it might be the barley pellets is they "disappeared" so fast and the water got foul and brown, not clear like it usually is.