Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Deicer / Dead Fish question

In Southern Ohio I am alittle confused what caused some of the fish to die very recently when I had just seem them alive not too long ago. I have several ponds so I'll try to describe each and appreciate any thoughts on this matter. I bought this property last spring so this is my first winter with it. The ice never got more than maybe 10" on any pond.

Pond 1- small 20' by 30' approx 3.5 ft deep. Kinda show pond with elaborate fountain system. I had 1 12" LMB, 1 Amur, 1 Paddlefish, 2 Catfish, 1 8" HSB, 3 BG, 3 WE tons of FHM & GS;
About 2 weeks before the ice melted for good I decided to use a deicer and made a pretty decent whole. I noticed the bluegill and some of the minnows swimming around the top close to the deicer. I startled them cause I used a flashlight to look in. Also saw the paddlefish swimming around. 2 weeks later 2 of the 3 BG are dead, paddlefish is dead and a WE is dead. Except the walley all of these were really close to the de-icer 2 weeks prior and now there dead. I have seen only noticed one large fish near bottom moving and gotten good look to ID it. Minnows are fine;

Pond 2- 10' by 40' only 3 feet deep. Another show pond; 4 10-12" LMB; 3 CC 2 of which were about 2 lbs; 2 WE; 2 Amur; lots of minnows; same deal with de-icer; large CC was near deicer. Found it dead on thaw along with 2nd CC; All LMB look alive and well; Have seen 1 Amur; minnows fine; Several days after thaw saw final CC; It was large and had a cut on its backside I noticed in fall; It stil had it and looked like it had some bad infections going on, seemed really sickly and I tried PP treatment in seperate container and it died which didnt shock me.

Main Pond - about 1/3 acre 5' deep; 2 Amur alot of CC and LMB, BG few large Goldfish. I put one paddlefish there but think it may have gotten eaten somehow after I put it in by a heron/animal or something cause I never have seen it swimming around and I always can see the large amur's and tons of LMB/BG; Never used De-icer here; When I would pellet feed tons of the CC would come to surface for food. I have not seen any floaters, ID'd both amur, Goldfish, LMB, BG; so all seems find there except when I throw food in water I dont see any CC come to surface.

Ok so if you managed to stay with me here are my main questions.

1) Can De-icer cause fish to die? Seems ones I saw near it nearly all died 2 weeks later and managed to make it several months through coldest winter I've seen here in my 30 years of life.

2) Should I be concerned about the infection on the CC that had a cut? I.E. pond water poor quality? Contaminated pond?

3) Do CC die before other type of fish? had some as big if not bigger fish that seemed to survive in the ponds but they didnt make it.

4) Should I assume all these CC dead in main pond or is there another reason there not coming to the top to eat the feed? They havent gotten any since last fall so maybe they forgot?

5) Are paddlefish more fragile than other fish in certain conditions? What would they be? Ones I had were just bought so they were juveniles 10-14" when bought in fall;

6) I know it on the forum but I've struggled to find info on what levels I should try to monitor. I've seen pH, O2, ammonia but what else is something important to monitor?

Again appreciate any comments

Believe it or not ice is an insulator of sorts. It prevents wind action that can drop the water temp even further. For such a small pond you probably chilled the water and it was too much stress for the fish. I.E. my small trout pond which is larger than your small pond dropped to 32.5 from top to bottom due to aggressive aeration. Fortunately trout don't have a problem with it, but if I had other species they would have been severely stressed if not killed.

I know of a fish farmer that lost fish in open water in early spring one year near Marysville, Ohio due to a freak snowstorm that dumped 21 inches of snow into the open water and killed some of the fish by chilling the water.



There's nothing you can do about it in cold water but wait for the water to warm when the fish's immune system will kick in. Ponds are really hard to treat if need be anyway. Typically disease issues are due to poor water quality. Take care of the water quality and you shouldn't have any disease issues.



Typically the larger fish go first when there are oxygen issues but it depends on the species. Some species can handle low D.O. even at large sizes, some can't.



The water's too cold yet for them to feed actively. I think you will know better when it warms up.



No idea.



You can't control Ph in your ponds and it shouldn't be an issue. O2 monitoring requires an expensive meter. Ammonia and nitrites shouldn't be a problem in a pond unless you have too many fish.

thanks alot for that fast and in depth response. Doing my best to become less amateurish about this stuff but I'm sure I'll do plenty more dumb things on the way.

Kobe,

We've all been there and continue to learn. Don't feel bad.

So just a thought but could a fish kinda shock itself if it were by the de-icer (warmer water) and I walked up and startled it so it swims away to the normal cold water?

The water may actually be colder at the deicer if the air temp is colder. Don't think their is enough of a temp difference for shock. The water closer to freezing is the stressor. Fish seek out the warmest water they can find, which is normally on the bottom at about 39 F. When you over do the mixing you get rid of this warm water (relatively speaking) refuge.

ok, I thought maybe right next to the copper coils on the de-icer it would feel warm but I've never tested this. I certainly can understand though that the entire whole itself would be letting in alot more cold water

When you are talking about a de-icer, are you talking about something that looks like this?

Kobe,

My bad I thought you were talking about a diffuser which some people refer to as a deicer. That said opening up the water in that small of pond probably reduced the water temps with really low air temps. Same effect.

esshup yes exactly like that and ya air temps got lower than I ever remember them ever being here