Welcome to PB.
The Green Sunfish only spawn annually and bluegills have a rolling, never ending, spawn. Thus, in theory, but only in theory, the bluegills should wipe them out. Doesn’t seem to happen. I have a 1/4 acre pond with only green sunfish that I didn’t stock. I stocked bass, bluegills, redears and channel cats. Over 40 or so years, the greens, with the able assistance of cormorants, have wiped out everything else. Where did they come from? No idea unless they came mixed with the original bluegills. I occasionally feed them and occasionally fish there. They will out fight a bluegill every time. I like them in this setting. This water hole is a mile from the house and I have another one to spend $$$$$ and sweat on.
The larger one, an acre or so, is close to the house and I spend most of my blood, sweat, tears and money there. I call it my cormorant pond and is a twice a year battle.
If your goal is a balanced bass, bluegill, and catfish pond, nuke it and start over. But, like teenage daughters, it’s a never ending challenge.
