Get some fatheads for bait and fish like hell. Since you know how many are in there you could fish them out. Rock bass really go for minnows. You only need to catch three to halt any potential reproduction.

Considering they are your top of the line predators right now they may not be that hard to catch.

And... I would have a word with your neighbor! ^%&%*# Ask him if he wants to reinburse your expense of putting in a pond and if he ever does that again...

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.