I went up to my pond after the ice melted and I found 2 dead 8 to 9 inch bluegills and about 12 1.5-2 inch gills . this is the first time this has happened after ice .The one in the picture is another one I found still alive but swimming on its side and it has these red spots on its fins still alive after 2 days of finding .Just wondering what is going on .The algae in pond has never been this bad thru winter just curious if this has something to do with it ?
I have heard of this in blue gill when they are stressed. Those fins are the first to go. Most of the time the stress is from low dissolved O2 or excessive other gasses taking the O2s place.
Guys transporting fish long distance have said those fins are the first to go from low O2.
Hope this helps and I hope you have lots of them so the loss is minimal.