Pond Boss Forums INTRO Questions & Observations Thread fin shad die off 9-11-18 -DO/Biomass issue?

On 9-11-18, I lost 20,000 to 25,000 TFS on my 9 ac pond in Chester, S.C. Pond has Kasco 4 diffuser system and 2-3/4 hp surface aerators running from 9 pm to 10 am daily. I also lost 20 LMB and 30 HSB. I immediately turned off 3 feeders and turned aerators on full time before loss of LMB and HSB. The majority of my remaining fish survived and will readily feed on hand fed fish food and readily hit a lure or fly.

I picked up 25- full 5 gal buckets of dead TFS but the most amazing observation is the quantity of TFS surviving. I have no idea of the quantity of surviving TFS but the number may be way over 100,000+++. I have no real way of knowing. Is this TFS biomass the cause of the die off? Do TFS create a biomass issue in ponds? What can I do to reduce the TFS population? Will appreciate your response!

Thanks POND BOSS for this forum.

Al Allison

First off, I am no expert that's for sure. But, bio-mass is bio-mass what ever fish it is I would think. Its sounds to me like a turnover in your pond. Kinda common for this time of year from my understanding. And with only 4 diffusers in a 9 are pond sounds to me to not be enough to properly turn the water over once every 24hrs. This opinion is based on my 3+ acre pond that I have six diffusers which was suggested by two different aeration companies. Reasoning was 6 diffusers due to ponds bottom structure with dips and channels and humps etc. I would think 9 acres might have a bottom of many contours. I have read where or when a pond turnover happens you most likely will lose your largest fish and the pond may repopulate on its own. I also have to mention I experience a large fish kill of TFS once but it was due to a large number of Cormorants where they killed off a couple of hundred 4" TFS along with a few large cnbg and a few HSB that I found in the mix of TFS. There were about 85 cormorants I found on the pond that morning. They do migrate this time of year and a pond like your might be a candidate for Cormorant stop over.

Al, I am sure an expert will jump in soon. But you asked on how to remove some TFS and so I will throw this out there. I can and do run a sein from time to time, mostly in June and I will get some TFS when I do, so maybe you might get a sein going if you think you still want to reduce numbers. Only way I would know how to reduce the numbers. In a 9 acre pond it would take some serious sein times I would think to make a dent if the numbers are really high.

Pre-event how were your various population conditions? If you had a partial die-off and still have lots of TFS including adults and are not predator crowded I would just watch for a while. With parts of the lake having plenty of O2 via aeration I would not be sure it was O2 caused. Fish will move to areas of sufficient O2 and do so often. Did you see fish crowding around the diffuser areas(boils) or surface aerators ?

Threadfin hate it when the temperature drops suddenly. Have you recently had water temp fluctuations?

Did this happen before the rains of Florence started?

Thanks for your input. The aeration systems were not running 24/7.The diffuser system covers 6 Ac. of 6'-12' water and the two surface cover 3 Ac of 3'-6' water. Now running full time and water has cleared and fish are feeding well. 4-5 cloudy days preceded the die off and plankton bloom was on the heavy side. Will continue to run diffuser aerator 24/7

ewest- 2-3 weeks prior to die-off-- BG and LMB became difficult to catch. Diffuser aerator was running 9 pm to 2 pm daily and surface aerators were running 4 am to 10 am daily. Plankton bloom on secchi disk was 12" to 13". 4-5 days of cloudy skies prior to die-off.

Now running diffuser aerator 24/7 and surface aerators 7 pm to 9 am daily. Hurricane Florence dumped 4 1/2 " rain this past weekend and pond secchi now reading 18". No further die-off and water now seems to be in good condition. No unusual activity at diffuser boils that I recall.

Thanks for your reply and dedication to the Pond Boss Forum.

Al Allison

I think you did exactly the right things. Keep up the process until the water cools and plankton lessens. Please report back.


Very high water temps lead to BG and LMB reducing activity and feeding.