Pond Boss Forums INTRO Questions & Observations Too much diffusion in a small pond stressful?

I've got about 45 2 to 3 lb. smallmouth temporarily in a 1/10th acre holding pond right now. Three ponds this size in the back acre with one airline going to each pond from a 1/3 hp. rotary vane compression. This really makes the water roll in each pond with a membrane diffuser at the terminal end.

I know that many fish in a pond that size is stressful enough, but they have been acting really weird, as in going up into shallow water with their noses pointed towards the banks, or in large groups huddled together as if they are cold or something. And feeding is sparadic on pellets, and they had no interest in red wigglers dropped in front of them this morning. Clearly stressed. One fish is even discolored and I've had about three morts in a week.

Well I turned off the diffusion to that pond today, and they seem to have stopped the weird behavior somewhat(my fingers are crossed), and I now see bluegills up high roaming around in the sunlight, which is what I normally see bluegills do in this pond this time of year as the water warms.

If the diffusion was stressing them does anyone have any idea why?

My thinking are the following possibilites:

1.) To rapid of turnover of the water was keeping any surface warming minimal, and they needed temps to rise for feeding and spawning? This may in fact have delayed the females, and could be causing them to be eggbound, as things this year are late. (It's been an abnormally cold spring up here).

2.) Supersaturation of nitrogen gas with that many bubbles in such a small pond?

Thoughts anyone?

Yeah, I know, there is an aeration category but I was afraid no one would notice this post. And I don't consider diffusion actually aeration anyway. I consider diffusers more of a turnover mechanism vs. aeration.

Cecil:

Your number 1 hypothesis is the right one. The only way to know if the pond is supersaturated is to see what the O2 levels are. at 50 degrees, the 02 should be a staturation of 11.3 mg/l, at 60 10. mg/l, at 68 9.1 mg/l and 72 8.7 mg/l.

We have the same happening with a carp pay fish pond here. The client contiues to run stream water through the pond, the diffusers circulate it and keep the temps at 61-65 degrees. This makes it so the fish do not bite and just like you they are not visible.

I'll check D.O. levels with my D.O. meter but I haven't had time to change the membrane and calibrate it.

So oxygen supersaturation levels are nearly as bad or as bad as nitrogen supersaturation levels? Since there is more nitrogen in air than oxygen, couldn't one have supersaturated nitrogen levels?

I had a fish farmer tell me you can "burn fish up" if you have too much pure oxygen in the hauling tank. I had another tell me although that is not good, it's not that bad either, and not nearly as bad as supersaturate nitrogen gas.

Thanks for the response btw.

Why carp? Seems it more suited to trout! At least this time of year.

You know Cary if the fish would just talk to us, but they won't say a word!

At least my wife says, "nothing" with a pouty look when I ask her what's wrong!

It's like night and day now that I turned off the diffuser. The fish are eating again and nailing pellets. One of these days I will be a great troubleshooter as I have done everything that can be be possibly done wrong.

I will eventually kick it back on but at a much lower rate.

They are not still stressed from being moved into the pond are they?

Cecil, All female SMB typically do not spawn each year. I assume non-spawners absorb their eggs and a high percentage of mortality does not occur from that in natural settings. I doubt the egg bound nature of your SMB is causing the problems you were observing. I often see only one or two successful SMB nests in a local pond that has probably 30 adult SMB in it. The owner never sees dead egg bound female smallies.

I have seen up to four dead egg bound females in my big front pond. At the time I had no gravel, stone, or anything like that for spawning strata.

I don't think so Rex. They have been in the holding pond since last fall. Of course it's not an ideal setting for them and they are probably stressed by that.