Gee,
@TheFishGuy, I am flattered — I think.... Unfortunately, I don’t know the answers. I just know the right questions to ask. I am also a firm believer in acquiring adequate information before offering advice, therefore, am not prone to wild guessing.
@jenniferva, I noticed in some previous posts you were having problems with dead fish. You have also had a “habit” of adding things to the water as a corrective method/prophylactic treatment, and you mentioned somewhere back about removing a lot of plants.....
It is always an unfortunate and confusing situation when something isn’t right with our ponds/fish, because often we (the pond owner) isn’t always able to figure out/fix the problem.
But, then, sometimes there isn’t really a problem at all, so much as it’s our own inexperience and not knowing what is normal vs abnormal. In my case, I have decided that most of the time there is nothing wrong. My strategies have been to observe, observe, observe — know my fish and know what their normal behavior is. Take measurements: check water parameters; assess my fish load vs filter efficiency; look at the current environmental conditions; ask myself, “what is different now that wasn’t there before?”
Do your fish in question LOOK ill or injured (since the other fish seem OK)? Have you recently changed anything about your pond (added chemicals or new fish)! What are your water parameters (pH, ammonia, nitrites, nitrates, KH)? What is your water temperature (not air temperature)? Are you getting any run-off from your yard? Is there adequate oxygenation (you mentioned aerators)? How many and what size fish do you have in your 2500 gallon pond? Get a water thermometer. What kind of fish are these smaller ones?
@addy1 mentioned fan tails, and yes, they will appear more awkward than regular GF, just because of their body shape.
Anyway, my advice: just keep an eye on them and continue to monitor for changes. My zone is warmer than yours, but when the temps. drop here and the water gets cooler, the fish slow down. If your water freezes over, add your deicer to keep a hole open in the water so the gasses can be exchanged between the water and the air. Don’t add any chemicals, and don’t make any drastic changes.
Hope this helps and makes sense. Blame
@TheFishGuy for his misplaced confidence in my abilities, LOL! Just kidding!