Pond Boss Forums INTRO Questions & Observations Is this a sign of iminent fish kill?

I'm new to Pond Boss and looking for some advice on something I saw this morning. I have a half acre, 15' deep pond partially spring fed pond with RBT, LB, CC, YP and BG. I have an aerator set up with multiple diffusers - using one in 3' of water for winter. I had the aerator off for 3 weeks while I was out of town. The pond has been ice/snow covered for most of that time.

Yesterday, I shoveled off about half of the pond and got the aerator running. This morning, I took a look at the hole by the aerator and noticed several large LB (bigger than I knew I had), and some large CC and BG tucked in under the ice at the edge of the hole in around a foot of water. Is this a sign that they are desperate for oxygen - or maybe something else (a spring warming the water)?

Also, when clearing snow from the ice - are you better to clear areas in shallow water (less than 4') or deeper (6-10')?

Thanks for your advice!

First question: it sounds like the former - your oxygen got low. Hopefully it's not to late as a diffuser is not the best thing to reverse this. In fact it can make things worse if it's too far along by bringing up anoxic warter.

Why was the aerator off?

As far as your second question I'll leave that for others that are ore knowledgable on that aspect.

The diffuser in 3' of water will be fine. I agree with Cecil, low O2 levels. If the fish that you saw were large, you might have dodged the bullet and just gotten it open in time. OTOH, you might have lost some of the larger fish even tho you saw some at the open hole. If you have another diffuser set in 5' or less of water, I'd put air to it too. Getting more sunlight into the pond is a good thing, and opening up some of the pond to let the water take in O2 from the air will help.

This will be a hard winter on ponds from North to South.

A surface agitation system would be best to transfer as much O2 to the water as possible in a short amount of time, but use what you have. It'd be better just to leave the diffuser run 24/7 even if you are away on vacation. I do in my pond.

Or put the system on a timer at least you could have set it up to run 8 or 10 hours a day?? I have mine on a timer as I don't run mine 24/7 I run it only from dusk till dawn. They work great!


RC

When clearing snow from the ice, it would be better to do so in shallower water so the sunlight can get to the vegetation and enable photosynthesis.
I think you opened the ice up just in time! Larger fish are the first to die in oxygen related kills, so if your biggest ones were still alive, then you should be good.

Don't want to be a negative Nellie but if the D.O. was low and the fish found it just in time does not get you out of the woods. This is significant stressor and you could see a lot of issues once spring commences.

I've see stressed fish develop fungus during stressful winter.

I quick plowed off the majority of our pond for ice-skating, but skipped a few strips as I ran out of time before work this morning. The ice is ridiculously thick and clear. I can see stress cracks running down at least a foot.

I don't have much bottom vegetation to create O2, just a few strings of very sad looking curly-leafed pond weed. No blooms to speak of. I am hoping the lack of rotting material on the bottom of the pond leaves enough O2 in the remaining water column for my fish. At least the pond isn't heavily loaded with fish, but I am starting to worry. It has been ice-bound for quite a while now, and the inflow in a small creek has stopped due to being frozen up. I think the frost line is so deep it has frozen the farm tile up that feeds it.

Only spring will tell, but I believe my choice of species has a decent shot of making it though being YP, WE, and BC. If the BC take a hit, it wouldn't bother me very much. They reproduce so fast, all I need is two left.