Haha, the fact that I can't tell the difference between a pike and a pickerel shows you just how often I've caught either of those toothy bastards... In the one year I've been freshwater fishing around here, only reeled in one small, accidental pike in the Passaic, so while this one was a mere kindergartener compared to some of the fifth-year seniors some of you guys haul in, it's still a personal best for me.
Re: the pond, it's located a block or two from the Passaic and I only discovered it because I was walking back to my car after getting skunked from the banks one day. You're really not supposed to fish in it but the day I walked by, there was a guy fishing in it who happened to need my pliers to get a hook out of a sunny. Since the offices were all closed and I'm discreet and respectful, I figured I'd throw a cast or two in and happily move on if asked to.
Re: how the pike got in there, my bet is on either flood overflow or drainage to the Passaic as a couple of people have speculated. While it would take a pretty heavy flood to get him from the river to the pond, certainly possible. There's probably a drainage outlet from the pond to the Passaic too.
Now that I know it was a pike, I have half a mind to try to catch him again and relocate him back to the big water so the bass can enjoy their own private Idaho. There are tons of sunnies in there, so it'd be like a Vegas buffet for them if they weren't getting mauled by the pike.
Mike