Cinder block piles are fantastic fish magnets. You don't want to put them where someone might accidentally run into them while swimming. Big ouchies.

Rip-rapped banks are also fantastic fish magnets.

Maybe think about doing some 3'-4' high cinder block piles in 6'-8' deep water, and a few rip-rap piles along the bank.

You'll want a loader machine to place the rip-rap. Cinder blocks you can just drive in with the truck and toss em off the back. It will be a lot easier to get it done before the pond fills.