I was thinking Pacu also or at least some kind of aquarium fish that someone threw in there. I've been fishing there since 1981 and have never seen anything like what Brian described (in fact I've never caught a crappie there either).

Brian - how was the water clarity? I guess it's not that thick pea soup like stuff like it has been the past few years in the fall. Maybe the colder summer has stunted the algea bloom this year.