While I can't completely rule out the "bucket brigade" of how fish colonize new waters, it is highly unlikely that any of this has taken place. I work at a Senior Retirement community. Privacy, exclusivity, gated entrance, fence around the property, etc. The pond is managed by Maintenance for the benefit of the residents. I get to fish there since I'm an employee. Catch-and-release ONLY, as insisted by many of the little old ladies that live around the pond; they view the fish as their pets.

I completely understand about stocking prolific fish into small waters, as this pond is beginning to become overrun with Bluegill. I've read, and firmly believe, that in a small pond setting, all sunfish caught should not be returned to the water alive. Even the Maintenance managers agree with that, but the residents (who pay our salaries) do not agree.

I don't know when I'll get a chance to talk to the gent's that manage the pond. Holiday weekend coming up, so they might not be in. I'm off today, and maybe Monday as well (my normal day off, but with the Holiday, no guarantee). Definitely Tuesday, I should see one or two of them; I'll ask them then.