. Anyone ever have this issue.
Usually the issue is too many. Is there any chance that the pond had bass (even just one) and/or larger catfish in it when you stocked the copper nose? Or other predator?
I normally like to stock a pond that size with about 1000 blue gills rather than 150. One single bass could easily eliminate those 150 original stockers before they ever spawned.
Story: I once had a small pond that dried up and when it filled back up I stocked it with hybrid striped bass fingerlings just for fun. Later I drained the pond to rework it...and guess what? not a single hybrid striped bass, not one...but one very fat, very happy largemouth bass. Nature finds a way.